The grosinger checklist is indeed minimalistically neat:
https://grosinger.net/tw5-checklist/ It integrates into tiddlers in a different way than yours, and I think, really, more flexibly.
Like yours there are issues fussy people like me have in wanting more features. Probably I most want drag and drop re-ordering if it were possible.
What is very interesting for me is the "surface editing". I'm learning from that. tx.
Best wishes
Josiah