I agree about the Unimatriz Zero borg. And I don't think that endgame was a reset. Voyager only had one true reset.I've been thinking about this, and really, with the way Endgame was written, it didn't close a number of threads that were left open, like:
-What happened to the Borg from Unimatrix Zero? At the end of the two-parter it seemed like the Collective was splintered and now there was a separate faction that was fighting the Queen to disassemble the hive. Surely a story could've come from here without having to resort to a time travel Borg episode.
-Instead of hitting the "reset" button, why not advance the story by 20 years?
-Forget the Borg and time travel, how about bringing back the Vaadwuur and maybe the Equinox crewmembers?
Seriously, the producers had a lot more options open to them that could've satisfied fans.
The problem with what you wrote about using something besides the borg is that it may be something you want to see but not everyone would want that. The fans will never be satisfied because not everyone agrees on what they want to see. You can satisfy some but never all.