I think the worst Tank right now is Ball. Problem is, if you buff Ball too much it can let skilled Ball players completely take over matches to an extreme degree. I think Ball could use some small buffs, maybe to his lethality, but generally his poor performance is more due to 5v5 and supports right now (I say this as a support player). I think Rein could use that extra 25 Armour back, as well.
That, plus nerfing some Support abilities (I think Biotic Grenade and maybe Discord Orb should be reworked) would be a better way to improve the Tank experience IMO rather than buffing the tanks to high heaven.
Pretty much. It’s not impossible, but you’ll be having a rough go of it.