Excuse me, I've read in the local TL that there was a words limit on Bonfire now, but what are you trying to achieve exactly?
The Fediverse is confronted to all kinds of abuse and the only time post length has been a problem it's been fixed forever by the "show more" button. If you want to prevent the circular consumption of low-quality posts (which is something that I want too!) well… a meta discussion/feditips extension would feel more appropriate, for example as a sort of built-in, decentralized wiki that the microblogging composer would link to on first login