I am a little confused by your words, but I will try to answer it as well as i can.
First of all, the Visuals. I do not know if you are mocking the complaints, or agree that it feels... lazy. This version does not have anything in common with old Swain. Old swain's key visuals where, Pet Raven, crippled, and transformed in to big bird. This new version, is just not crippled. If you think so, then 99% of lizards are crippled. Big Bird ult in not there anymore, as they said "it would feel like he loses control" I leave that for others to decide. As for the Pet raven, they are in his Passive, and recall. But from the art work, and how much in the background, It seems to have been an after thought. Hell recall seems like they added raven last min. It looks like they where going to have a random ball of energy come up, and he uses it on his demon hand. The concept Art work I have seen, does not even depict a raven, save his ult form. So I am willing to go out, and say the Artists were told to make, imposing dictator design, and they did not know who it was going to be till later.
As for Game play, Well that is all subjective. Some people like tanks, others like supports, and others like to get pentas. Not everyone likes DoT game play, or slow game play. But Swain is a product of his time. They where churning out champs to make sure they have a 100 different flavors. So What you see with Swain's old Kit was the Fact they just made a ton of auto hit skills. And lets be honest, Riot is making rounds to remove this from the game. If you reworked old swain's spells in to skill shots, Swain's old spells would be more inactive for both players, then most spells. Make Q work like leblace's tether and E, they could have turned that in to a skill shot, say like Ryze Q.
Anyway, Is you got hit Q, you had 2 options. 1 back off, to reduce the damage, or 2 take the damage, to keep harming Swain. It also gave more counter play for you and/or team, to (A) get in range, (B) react to the incoming damage, or (C) skill get off cool downs. Hell at level 1 Swain's Q/E was countered by a potion. That thing everyone can get at the start of the game. As for Swain's E, it is just like Vlad's Ult, if you want to do more damage Swain Had to go ham. It boosted his AA so he wanted to go Ham during the 3 seconds, resulting him staying in harms way if he did.
Now on to What they could have done with his skills. I want to note I am not an expert at building kits, so expect... bad design. First of all. Lets combine Victor's old Ult, and Ori Q. So for new Swain, when he uses Q, he loses 100 mana, but for 30 seconds has a 100 unit size bird storm ball that he can direct any play with in 600 units of himself. if he moves out of range, the ball will follow him. Give it 10 true damage per sec, removes 1 Mr per sec, and a 1% ap ratio. I am cool with that. Then on to W. Lets make it plant the Q in one place. It last for 5 seconds dealing the normal Q damage. During that 5 seconds, each time it damages a opponent, it doubles in size and gets a charge. after the 5 seconds, it burst forward, and makes any opponent hit by it deal less damage for 5 seconds. Amount based off charge. I think this is impossible to balance, however it shows that with a DoT you can really make the game play about the spell. ( you want to keep them in the spell for a bigger and better effect). that is all i can think up off the top of my head. However I think I get the point across.
If not tho, the point is, DoT spells can be played with far more, then the generic Burst spells. Because of the very nature of Burst, that is it. Unless it has CC. Then it adds something your team can play around with that is not "did it or did it not just kill the target?''
As for the unlimited Mana, Are not there high elo players complain that Riot has made some champ mana cost so cheap, they might as well not have mana? Mana in this game is not like DotA, so I find that argument pointless. Because as we have seen with URF mode, worrying about can or can I not use my spells is just not fun for most players. So Riot has responded in kind.
