Yep, I can't take anyone seriously who claims to be "unbiased", yet asks for buffs to Deathstroke, who is by far one of the strongest characters in the game already. I can see the issue with his trait, and something should be done to change/improve that, but aside from that, he needs no buffs whatsoever. I also can't for the life of me see why anyone would think that The Flash needs nerfing at all! The Flash is just fine as he is.
I really hope NRS don't go down the same route for Injustice as they did with MK9, where many of the buffs and especially nerfs, were entirely unnecessary. The hotfixes generally broke just as much as they fixed. My main issue with most people talking about "balance", is that in reality, they just want to make their own characters as strong as possible, and any character who they have difficulty defeating, nerfed. As someone who has no "main" and uses the majority of the character roster (not just in this game, but in beat em' ups generally), I have no pro/anti-character bias at all. I like variety, and a balanced game need not (and indeed, should not) mean that every character is the same strength/weakness wise, with the only difference between characters being their different looking special moves. That would be very boring to me, as it would take a lot of character specific strategy out of the equation in matches. I also have no real issue with tiers in general, it's only a problem if a character is truly OP, or is extremely difficult to win any match with, regardless of match-up.
Right now, I'd say that Superman is the only character who is OP, and I'd have no issue if he was nerfed. In saying that though, he is definitely not as OP as Kung Lao was in his release day state. Other characters need slight tinkering with, like Cyborg's trait which as of now is useless, and Bane's extremely fragile state after using Lv.3 Venom. And perhaps Doomsday's Supernova unblockable needs to be nerfed in some respect, but overall, I think this game is nicely balanced, and doesn't need much doing to it. I've only had the game just over a month, so I don't know how much has already been altered since the game's release, but certainly, the game as it is right now, only needs a little tweaking for it to be just right.