I like the scheme, 7 girders were always too much even with limit, but selects make up for it adding some new degree to the scheme, making it something almost entirely new, focused more towards action with deeper planning. But I dont understand why nana and cows arent chanced equally like the rest of weapons - scheme isn't fair by it's nature, and there are plenty other weapons that devastate just as much (and cows are rather tricky in this scheme, so that's an even more unknown to me), plus it's not guaranted you will be less likely to chance nana in a crate (see my game vs VoK).
Islands only tourney next?
As for myself - while double-cavern layered map is somewhat fitting T17 and thanks to that this theme is actually being used, I believe the concept is outdated and is one of the main reasons why T17 is that problematic competetively. Even these 2 selects worms aren't completely fixing the state of the scheme, they even bring some other problems that I can notice but am still unsure about, that would require some long-term insight and testing by pros. But with the transition to island maps (perhaps just for testing for now) T17 could be different and selects would make much more sense.