I'd like to see the current 5/5 talents increased to 8, like the rest.
Revitalize is especially one I'd like to see increased with something like 6/7/8 adding faster energy recovery of varying levels, on top of starting with the full energy bar.
Or maybe instead of energy recovery, Revitalize lowers the cooldown on heroes who have one by 10%, 25%, and 50% respectively.
Heaven's Wrath, Corrode, and Condemnation could increase the chances of their ability firing off, since I don't think they need increased power so much as to actually go into effect more.
Enlighten 6/7/8 could increase the percentage of experience gained to 125%, 150%, and 200%. True, I doubt most would use the 7 or 8 on this, but I could see using the six for sure.
Psyshield could give more HP for 6/7/8, and at 8 also reduce the time between shields to 3 or even 2 seconds. Kinda winging it on this one, since I don't really have any experience with it, beyond Squad Showdown.
Move along, please.