BBR's changes to Classic CryptoNote are not small. BBR's block chain changes make it at least 50% smaller. That is just one change.
So go ahead fork Monero then, but keep the perfectly sized blockchain intact. (That is the value, the blockchain ledger with everyones holdings)
Monero is young and can still grow, a hard fork would be a loved by investors if it brings in even better functions.
I think in general the altcoin scene is too afraid to hard fork, there is nothing that hinders a hard fork of Monero at this point. Monero is not old like Bitcoin, it's a perfect coin to hard fork and keep the value intact. That would only raise confidence.
That is Monero's decision to make. I don't believe a CryptoNote coin has ever been successfully hard-forked. There may be unexpected consequences.