I have seen it said (and know from personal experience) that Wolverine compared to the other 90 cost heroes just doesn't quite cut the mustard. How would you fix it? Here are my personal suggestions.
I would implement an ignore defense element to his adamantium strike and turn his healing factor into a quick action. While both of those are ok right now I honestly think that the Adamantium Strike is lacking when you compare it to his Brutal Slash. Sure Brutal Slash does a whopping 30 damage less or so but I get the ravaged debuff with it. That turns all those bleeds into double the damage and a 5 bleed for double more then makes up for the 30 damage I lost using the ability. Healing Factor is another one of those that could most definitely use a slight oomph for being a level 9 skill (compared to all the other 9 skills) and I think making it a quick action and leaving everything else regarding it as is would give it that oomph.
Hopefully we can figure something out to make him better because no matter how much I have used him (and I have used him a lot lately) he just doesn't cut it when you compare him to the other 90s.