Here's my thoughts on possible buffs, or ones you guys mentioned that I liked:
-Have her do more damage to or have increased crit chance on marked targets. The whole idea behind her is that she instills the fear of inevitable death in those she marks, and maybe it'd be a bit too strong on champions, but at the very least give her the ability to take her marks quickly when she gets the chance.
-Similarly, give her vision of the marks. Additional attack range would help as well, but she needs the ability to keep track of and take her marks, not just the "go get it!" from Riot.
-Lamb's Respite in reverse for enemies. Keep them unkillable the same as Kindred's teammates, but instead of heal deal damage to them when it ends. It would make enemies think twice about engaging in her ult, but not unthinkable. It would require greater timing and better positioning, rather than a "redemption for everyone...!" kinda feel. Another fling on this would be to reduce the heal towards enemies per skill level, along with increasing allies heal, or even giving allies a bigger heal for each enemy caught in it when it ends.
-"change the slow on kindred's E "mounting dread" into a stun" I both like and dislike this idea. Once again, this is not an attack in and of itself until the third hit, but rather it is a mark. The effect should rather be "slow until third hit, then stun". Try pulling a jungle camp with your E; it doesn't work. Changing this would also allow for actual synergy for her ult. Currently the best you can do is to try and time a Q for just after it ends, while a mark then stun would actually allow the ult to provide Kindred an advantage...!
-Wolf base lifesteal. I agree that the purpose of Kindred's W as of now is simply to reduce her Q's cooldown, which doesn't seem to match the whole idea of the ability. Lifesteal would increase her ability to clear jungle effectively, as well as make engagements in an opponent's jungle much less deadly for Kindred. She's not a ninja, so trying to sneak around doesn't feel right. It should feel like a HUNT...!
-Let her mark all enemies at once. Yeah, that sounds overpowered right from the get-go, but if you use the same "unmarkable" cooldown on marks earned from enemies and also only allow one mark from enemies within a certain time frame, the same cooldown as remarking takes, it becomes a much more reasonable idea, does it not? Currently it feels almost counter-productive to gank unmarked lanes, and that should never be what a jungler feels like.
-Mark's visibility. "making it so her jungle mark isn't visible to the enemy team unless they have had vision of it just like with the jungle camp itself" is exactly what I'd recommend. It makes no sense that an enemy would know exactly which monster Wolf wanted for dinner unless there was some kind of visual indication. Just that one change would make her so much more fun to play, because you wouldn't spend the entire game paranoid that someone is either taking your mark or waiting to kill you the second you did. It would make your enemy jungler use vision, be punished for a lack thereof and rewarded for using it with a potential kill, but nowhere near as reliable to kill as it is now.
-Mark placement. Give her marks in her own jungle, too...! That in addition to the visibility would be perfect, but when you are forced into the enemies' jungle regardless of how the rest of the game is going... Kindred has no way to come back from a bad game because her marks are so far into enemy territory.