Hello,
This is the very first time I post on the boards of LoL, but I feel very concerned about Swain's rework as I really love how Swain was since his release.
I come here in the hope of giving feedback that can be seen by rioters to help the team who work on him. I hope too this is the right place to do so.
First of all, I'm sorry if my english makes you bleed, it is not my native language.
Moreover, I would like to note that I do not own a PBE account but I'm following every gameplay I can so that I have a precise advice. In case this can be any useful, I'm from EUW.
Gameplay
I'll start with that. Swain's old gameplay, as it may have feel somehow "clunky" or "poor" gave me mechanics that I liked playing with :
I liked the passive, even if this mana regen was feeling "gadget" I like the way I was imagining Beatrice harassing dying enemies to stole parts of them to give ressources to Swain. His new passive kind of keep this feeling with a much more "demonic" aspect and a leeching life mechanic instead of mana. I really like the idea and pretty like what the rework did there. The little plus of pulling the enemy in case of a cc is a cool mechanic.
I like his Q spell sending Beatrice (in old time just giving the order to Beatrice to... Fire laser? Against an enemy). What I liked there was the slow, the fact that it becames a skill shot where Beatrice could "zone". Now the reworked Q is some kind of... Electric? And have the mana regen mechanic. I find this spell okay-ish in term of gameplay, there is no problem.
His old W was his snare, Nevermove. I really loved having a ccing skillshot. Now, the reworked W is just omg, this is my favourite skill. I love the idea of scouting as being the Grand General. Planning actions, gathering informations (litteraly because it triggers his passive). But the first iteration of the skill on PBE feeled too "damaging thing" as I was seeing it more like "tactical and damaging tool". You made changes recently that are more in this way so I'm totally with you. For me, best part of Swain rework.
His old E was a... hum... a ball? Idk, that was something point and click and juste basically doting and increasing damages dealt by others spell. This was meh. His animation doing it was meh too. Now, it is his Nevermove ability, and I like the new way it is. Really like it.
And now we come to his ultimate. I loved Swain's ultimate, turning him in a fucking bad ass midway bird human weird thing that was menacing. He was draining life while dealing damages, and just kind of liked taking bath in enemies. But I was sad it was only that, I wanted a more tactical skill, with reflexion behind wether or not activating it. What you did with the rework feels midway. First of all, I'm kind of sad Swain do not send birds anymore. But you did it on his passive where birds fly to him, so for gameplay clarity I understand. No problem. But, this transformation feels... Poor. I know you wanted him to have control. But I don't see anywhere a demonic bird. I just see wings. Beh. So I kind of like his new mechanic but don't like the way it's been realised.
Visual, identity etc.
I would like to say I've read your champion insight. Before I start giving my advice on reworked Swain, I would like to say I really don't understand how you could just pass through the fucking birds. I mean, you did really great pieces of art about researching the aspect of the demon bird, I loved it, and you just say at the end "Uh we added birds and wings but it was not our main concern" (to sum up). But your ideas were great! And I just don't understand how, instead of just placing birds around Swain to say "it's okay birds are there now even if it was not our main concern" you didn't just transformed Swain into half this demon bird, to show he is in control, show he's still humain, but make his hand more non-human-frightening-thing-that-is-a-threat-while-you're-near, give him bird-like wings but with an ominous' style, not angel's wings that barely flap... I must say I am disappointed yes. Only the reworked Tyrant Swain have the transformation I imagined, with eyes ornaments on the wings, and a frightening bird head instead of my proposition of his hand/arm being even less human.
So now, after this little over the place paragraph, I'll start with how Swain feeled like for me.
Swain was, for me, this hidden grand general. He did really greatly hide his strategy, and was some kind of weird/secret person, giving no informations about his feelings (such as pain from his broken leg for example) and very stoic (his league judgement). As I play him, he's often "come on, kind of punkish grandpa, let's move on and just be a secretly nightmare to enemies that think you're just not a threat" as I feel he is so much more powerful (in his lore) than someone can see when he's just walking weirdly as he did prior his rework. For his skins, Northern Front was for me a mix between Swain in campaign in Freljord and Swain with a Russian design. Bilgewater was just fucking pirate and do what you want 'cause a pirate is free. And Tyrant, it was just Swain in his splendor, wielding a staff that he suddenly uses as his cane because of who he still is.
Swain's rework now in my opinion. Where should I start? Let's begin with splash art.
I really really like the composition of this piece of art, and as I've seen the first proposition, referring to a more "propaganda" splash, I understand from where this splash art came, and I just love it. The design of the hand is just beautiful, "Beatrice" (i'll talk about that after) near Swain is just badass, his clothes are super cool. But... The head just does not feel Swain at all. The first iteration of the splash had the perfect head for Swain. Not the currently. I don't have problem with long hair, or white hair, I use to really love white hair. But with more nuances, I see his hair much more like his rework model in game. But I've seen you were currently discussing this point, so, my only remaining concern is for his head. Swain's face looks like the first proposed splash, where he is more stoic, with less curved eyebrows, less carved cheek, not the one currently on PBE. In fact, it is more about his expression than his face as I write it.
For the other splashs, I have nothing to say, I love them all.
Now, talking about model, here I go. You said you removed the limp and the cane (I loved the fact he has a limp and a cane so I'm sad they're gone...) and replaced it by a leg brace. I'm okayish with that, but... Before you said there was a leg brace, I didn't even notice it. That's my problem. It is not evidence he has one. I would like to have the opportunity to see it. Maybe show more the leather laces... That's my first point, my second point : I find Swain too massive. I don't know if it is the coat, but he makes me feel more like I'm playing a mercenary than playing that finest tactician. I don't know what to propose to fix that, because I have this sentiment only when seeing his back, since when we play a character we only really see his back while we are in the fire of action. But when I see him feeding his "BeatriceS" for example, I do not have this feeling. His model is perfect despite my feeling, so I would touch nothing fearing to break the harmony you created. Oh, and I love the coat.
Last point, as I said, I don't really like his transformation but, I can largely understand it is not changeable, but since, I don't know if the VFX is a WIP, but I find it too flashy, too present (for all skins). He's already floating above the ground, he's largely visible, he doesn't need to glow like a lightbulb, or at least less. As I write this too, I can maybe understand the glow is a clue to the current loading of the second part of the ultimate. But still, this effect is not attractive.
Talking of VFX, here am I. His Q is too red!(base skin and so bilgewater) I would prefer something darker. His w and e are perfect. I would see it with more black, the fact it is electricity bothers me, but it is my opinion and it's not enough to want you to change this. So in the end, I would only make it darker.
Now here is Beatrice. Many said RIP Beatrice because of the quote of Swain "Which one of you is Beatrice again?" and because we also lose this birdy creature at our side. But your sentence "Let's just say we didn't murder Beatrice... we made Beatrice a murder." makes me very curious. I, for sure, will really really miss Beatrice by my side, but Swain is reworked, I can make compromises. But THIS sentence. There is so many interpretations. I like to think Beatrice is just everywhere. This is frightening. I like it.
Ah, before I forget, I love the back animation of Swain, but the one of Tyrant Swain, I really really dislike it. I would largely prefer having the default animation as I feel Swain is having birds as his tools and companions at the same time.
As an overall, I feel like Swain is less original than he was before, but that originality was kind of punk and messy, as you stated in your champion insight. So I can understand all the changes, and, after all, a character is defined in his own way by each person that like him. What makes me kind of sad and angry at the same time when I read the champion insight, was the fact that at some point his transformation was not guaranted, it was just THE thing I was afraid of disappearing and it could have been reality. Glad it didn't happened, and I really thank you for your hard work keeping this aspect. And your hard work overall because this rework is really super cool, even if I kind of liked his green color, I easily understand the need to clarify the color pattern of each faction, as I had the opportunity to discuss it with a person close to me that plays league too.
I hope Swain will not become a spamming mage with his low cd q, I want him to keep the warlock/general close to his people in the heart of battle, kind of tanky and big threat at the same time.
swain was a mage with hard to hit abilities that would reward you with massive damage if you managed to hit his combo. This 
is Tom Clancy).
