CTV is a short-cut, and I have trouble evaluating whether it's the right shortcut! Interestingly, CSFS is more straightforward: it's just one part of an existing opcode, after all.

ln symmetry would be a rework, but not an unimaginable one. For CLN, we have a specific daemon which handles channels in the "normal" case (channeld), and we'd probably just write a completely new one for LN symmetry.

There are two things I'm aware of: one is the idea of batching withdrawls to lightning channels which is made less interactive by a covenant (https://x.com/Polyd_/status/1714566295813841117). There was also an issue with requiring another round of interaction during HTLCs which Bastien Teinturier believed could be avoided, but I don't remember the exact details either, sorry!