Never want to increase inflation eroding STEEM or SP balances. Never want to reduce existing token balances.

Other than that, I consider just about everything on Steem fair game, at least for now. It isn't a platform built on a core ethos of immutability (unlike, say, Bitcoin) beyond the point of protecting balances. The goals of social engagement and rewarding are inherently experimental and challenging, and DPoS with a small validator set is designed to facilitate upgrades, so everyone should understand that this is intended and going to happen.

That being said, I'm also not in favor of changes being made unnecessarily or carelessly. But the question didn't ask about that so I won't elaborate on this aspect.