It sounds like your polymorph system is an improvement. Being able to easily register the polymorph events you mention would certainly allow many ways to deal with the spell slot clearing issue (and many others) in polymorphing.
I don't know that that is a fix for the actual issue the OP discusses in this thread (ELC clearing spell slots from Great * ability feats), but it's good to hear of another solution to the polymorph issue.
Maybe, just maybe look at my work and dont judge it based on what The Krit said about it. I find it quite annoying when ppls are discussing bugs and issues here that I fixed 4 years ago already.
I don't know where any of this comes from. I have no idea what issues The Krit has with your patch. I have never seen him here discussing it. The only potential thing I have heard here about the CPP that concerns me involves changes to the spell system (how Empower works, how certain spells work, etc.) that are more design decisions (e.g. bringing things into alignment with some version of PnP mechanics) than bug fixes. And, anything I read about that is likely old information.
Anyway, it serves little constructive purpose for you to assume that those unaware of some feature of your work must be unaware because they are judging it based on some critique you perceive as unfair.