To make such changes, commercial products I've worked on did these steps:
1. test with some users in 1:1 sessions
2. incorporate the feedback (or consider dropping the alternative, if most all feedback was negative)
3. implement metrics
4. launch to 0.5 - 1% of users. See metrics AND feedback.
5. incorporate feedback
6. gradually launch to more
7. at some point, remove the old way
I agree it's hard to do these with volunteer work. That's how some hard issues are never solved, but Gnome gets new apps or rewrites on existing apps with almost every release -- that's the fun work. It's volunteered, so take it, or leave it, or DYI, or pay somebody.
PS: I've reached out to a few Mozilla staff via LinkedIn with a proposal for a new commercial product, but nobody replied. Anyone has a contact there? Proposal: A Google Suite alternative for businesses, provided by Mozilla both as a cloud service and on-premise. Dual licensing, AGPL and Enterprise: https://docs.google.com/document/d/17czxzh20c8ouhrX-iZPS2BH8...