In my opinion balance changes are really needed, so that a game does not become stale. I agree that I would rather BUFF the weaker SPs and keep the current top tier SPs in their current states with some little tweaks here and there on the buffs (lets be honest seer shield is too strong, scout buff too annyoing to deal with with the 7k cap, morale&hawk give too strong options etc.).
Its important that some SPs are better than others, thats what creates a META in a game. But its also as important to change thing up with some balance patches here and there. Some of these SPs havent had changes in YEARS, when the late-game looked completely different. Ive been playing on Vendetta now for like 8 months and I enjoyed it for the most part, but i would lie to you if I said that seeing the same SPs over and over again is very stale and in my opinion bad for the game.
Also, I dont think any class is overpowered, more like some SPs outclass others just so hard that it may seem that way. Anyways I am very for balance changes, at least once in a while. Even if a potential REWORK of a SPs fails, because the SP gets overpowered or underpowered, it is still fixable.
I would not expect a complete balance patch with perfect changes, but one/some changes every once on a while on a SP would be enough already to keep this interesting.
Thanks for reading.