Imo Batman, Atrocitus, Black Adam, Superman and Aquaman have the best traits.
Batman's trait IS DEFINITELY THE BEST TRAIT IN THE GAME. It completely ignores any neutral game when out, hitstun for days, makes everything safe, recovers pretty fast, combo extender and is even effective at it's level one state. Sure you can pushblock it away but his trait still builds fast and batman doesn't need meter to hit like a tank so when it comes clash time, you're screwed. This trait needs to be reviewed and dumbed down. Activation of trait takes a bit longer? Hitstun not as good?
Atrocitus is hella dumb for sure, safe pressure, safe 50/50s, big damage and can be utilized at any range. Why I personally don't think it's better then batman's is a pushblock can negate the trait halfway and send him a good portion away from you. Still having to spend meter to negate a character with a strong trait that can capitalize without much meter needs to be reviewed but compared to batman, it's not nearly as strong.
Black Adam, the reason I don't think his is better then the top 2 is simple. He can be hit out of it and his trait requires him to be close. I feel like his trait would be more fair if the damage scaled within his combos and he received A HUGE DAMAGE NERF. 400+ of ANY CONVERSION SHOULD NOT BE OKAY!
Aquaman is simple, he slips out of grounded combos which for almost any character, is how combos start. It's essentially a get out of free jail card. Mix that and a pushblock with aquaman's dominating space control and it's pretty damn amazing trait.
Superman, he gets big damage, free pressure and mixed with his fast attacks, can break all armored moves EVEN SUPERS. It is an EXTREMELY effective trait.
Worst that I have the KNOWLEDGE OF is jokers.
While his trait in injustice one was ass, the parries themselves were very useful. Though they weren't active for very long, 1 frame high and low parries often caught people off guard while applying brain dead pressure, making them respect joker a bit more. The speed boost was useless, only useful on his amazing J2 that indeed rivaled batman and his J3 that had a deeper cross up in injustice 1.
Injustice 2 Jokers trait is just terrible. 3 levels. First one is useless. Second one is awful but better then the first and the final level is better but useless.
What made his trait somewhat effective in injustice 1, as far as speeds concerned, was that his j2 was so ambiguous, you couldn't tell how it would cross up and with his already small jump arc, the man could pounce on you for days. Same with his j3. In injustice 1, jokers j3 had such a good cross up mixed with the fact that the only way you could anti air it was if you hit jokers body and not the crowbar, made it extremely scary if he had level 3.
Injustice 2 Jokers trait takes way too long to get to the only "useful" part of the trait. It's not active for very long. His Jump 2 AND 3 were butchered and those were the only things that really benefited from the trait AT LEVEL 3.
In a nutshell, his trait is absolute ass NRS. Everything from how to get it to what to do when you have it.
Thank you for your time.