This idea is really interesting to me but it seems like it would be hard to capture a similar kind of fun as progressing in a traditional metroidvania. That there is a trade-off between player movement abilities and map shortcuts is interesting enough to warrant a purchase (big fan of the genre, personally) but "100%" saves and the like could possibly be un-fun to make.

Although, I'm already imagining a sequence where you trade away your last movement ability and walk down some long-ish path to a place where you get all or most of them back (or different ones!). That could be fun and rewarding but it would definitely have to be done right.