Now I'd like to focus on the obvious top contenders, but I'll begin with the big one- Revenant.
With the cool looks, cool voice, cool video, and even admittedly cool kit, it's clear to see that Revenant just doesn't quite live up to the hype and has been consistently placed at the bottom of every tier list. The primary reason for this obviously being his Death Totem, so I'll start there.
The two MUST HAVE changes here are as follows:
1. Have it so that you don't have to interact with the death totem for it to take effect. With an already long animation sequence, limited range, and lack of other abilities, I would suggest this minor change so that you could save teammates in a pinch, and have at least some level of useful grouping prior to having everyone chasing down this giant, obvious, glowing obelisk. With this of course, people wouldn't have to follow you and all get stuck in the same spot at the start AND end of the fight. With this change, being that it is now automatic, I'd suggest removing the ability for enemies to use the death totem- but with this buff at least they would have to earn it a bit more. The death totem is already super obvious and while I haven't played him much yet, I also heard there was some sort of visible tether? The list of issues with this ult isn't easily made into a short one.
2. DO NOT TAKE AWAY THE SHIELDS while ulting. I would rather respawning in a place with 1 health and 0 shields, where at least the ult has SOME value, rather than solely handicapping our team. Fine if someone comes prepared to counter it by camping your totem or placing Nox gas. That's all in competitive spirit and they'll have earned their kills. But until that point, this ult only takes value away from your team since it only takes one clip and fully negates everything you've worked to get throughout the game.
At worst, fine, you could put a totem near armor, grab it up, and insta-"heal" back to 100 shield but that requires careful planning and consideration, plus it still retains all of the weaknesses that go along with the fully destructible, super obvious, enemy abuse inviting trap, that is Revenant's ultimate ability.
As far as revenants other abilities, sure- I could see some changes. That being said, they definitely come second.
For his passive, I think one simple solution to what seems to bother most would be to make him more silent on the regular, or even just reducing the slow on his climb. Seeing an even greater range might be stepping on pathfinders territory and I'd prefer him to just stay the sort of fast paced solo assassin regularly.
For his tactical, damage over time OR remove the damage entirely and just add a bit more range. It's cool that it helps out a bit but negating people's abilities can already be a big deal, so I don't see much need for change there.
Now for the easy stuff-
His ult could definitely see a slight improvement; I saw someone else suggest the clone party as his ult and thought if not that, at least have his clones cause some chaos. It would fit the character and having them run around randomly might be able to give a second of cover and confusion, where the clones as is are entirely negative. All they do is give away where you are if you were in hiding.. just make him go invisible if they're not going to help.
His tactical having two charges could be nice but his ability is pretty fast. That being said, two clones would open up a massive list of fun tricks and it just makes sense being that you can use two during your initial deployment.
Overall, clones are clones. Climbing and interacting aren't all that necessary but sure- those would be fun if you strictly wanted to make Mirage meet Gibraltar status in Meta.
His passive is fine regardless of those who'd like to see an extended duration.
As is, I don't mind his kit so much and find him to fit in pretty well. Heard something about a heal while swapping guns, but other than that my only gripe would be the fast healing(stepping on lifeline's toes for no reason). He is a tank and should continue to be that. My only real suggestion here is that while in his bubble, rather than fast healing with items, either he gives back 25 shields, has temporary shielding towards allies(warding people off from rushing), or that the shield had some sort of slow effect on entry, so that there would be some reasonable delay to those that would want to jump right in. For teammates, this wouldn't be a detriment as they would ideally either sit and heal, or just take a second for the slow to wear off before acting again. For enemies, it would strictly ward people off for a brief second or at least give them a little something to consider.
Bangalore- perfect. Top tier and well rounded.
Pathfinder- perfect. Another top tier and fun.
Wraith- Fine if people don't love the idea of what might seem like a MINOR "buff" but the trail could easily be left off while invisible but instead give her a more obvious reentry.
(I don't even play Wraith, I just think it's fitting since her ult seems to show that she really does enter a separate dimension and should therefore show no sign of existing here).
Lifelink- awesome, keep her as is.
Caustic- the slow on the teammates is annoying but completely avoidable in most situations. He's fine.
Sadly I've yet to play Krypto the super hacker or his other techie friend but I'll try and give an update on them if ever it seems necessary. For now, they seem to be top notch characters with well rounded kits and I don't see any need for change.
Well assuming shadow form kept your shield and health at regular, there would be no reason to not want to go into it. Then when you die, you respawn with 0 shield and 1 health, effectively just automatically teleporting you to safety but EXTREMELY vulnerable.
I mean, I guess if you have a self rez or something.. otherwise, I'd prefer the teleport to being dead lol maybe a pop up on screen or a way to cancel it?