[Dids]

I don't think there's any way to hammer home to people anything meaningful without bans/suspensions. If you're looking to change behavior, you've gotta have some muscle behind your actions.

Why are they a bad thing?

I wish you would elaborate on "What you don't see, though, is the entire picture of exactly how many users are being banned for how long and for what reasons."

Any kind of system of escalation doesn't help much, because even a perma ban just isn't enough to deter people from coming back. Unless the new software really helps make a ban stick, I don't think warnings stop anybody.