I like the idea of it kicking in below 25. It gives everyone a level playing field, but if you attract the constant ire of Steemians because you're posting spam and junk, then you deserve to slowly have your ability to post nonsense reduced.

Your proposal is a little less aggressive having it apply to reputation less than 25. If this applies to both posts and comments, that would be amazing. It would prevent the constant abusers spamming. Although it wouldn't stop spammers from creating new accounts, that's a hard problem to tackle without targeting a few innocents.