Hash chained covenants in general all have about the same plateau of functionality, which seems roughly reasonable to add to Bitcoin as it is today but suffer from being limited and hence likely only a stepping stone to greater functionality and unless whatever's put in now cleanly extends to supporting more in the future it's likely to turn into a legacy appendage which has to be supported. So my generic suggestion for this sort of thing is that it should be proposed along with a plan for how it could be extended to support full-blown covenants in the future.

Another probably unhelpful bit of feedback I have is that Bitcoin should probably be taking verkle trees seriously because those can have substantially lower size/cost/weight than merkle trees. That doesn't just apply to this proposal, but to Bitcoin in general, which doesn't seem to have any serious verkle tree proposals to date.