i think the main issue is the lack of flexibility and expressiveness compared to something like TXHASH, the other is you need a new script version to define new flags.
in case the consensus emerges that we can’t do TXHASH, it would be worthwhile to reexamine SIGHASH_BUNDLE and APO/AS. especially if we say do a tarpoot 2.0 where we fix the biggest blunders of taproot, then including new sighash modes in that script version might be worthwhile.