Do you know why they're planning to drop Firefox? And why would Chromium never make it on there? I don't know much about F-Droid and its limitations.
EDIT: Okay I did the Google search that I should've just done in the first place. Apparently they're not dropping Firefox fully, but rather forking it to "remove the proprietary binaries out of the official builds" (Google Play API, etc). I suppose APIs like that are important enough to your use-case that you need an alternative source for Firefox?
This is presumably why Firefox's removal has been continuously postponed. Reliability is one of the reasons why I would prefer first-party Firefox over a third-party fork.
Though there are good reasons why F-Droid doesn't include Chromium and seeks to remove Firefox, the absence of many open source Android apps from F-Droid's catalog has a direct impact on utility. It's also not uncommon for apps on F-Droid to lag behind the version on Google Play or the latest release direct from the developer. (Again, there are good reasons why they screen apps, but it does impose a delay.)
I appreciate F-Droid's screening process, and I wouldn't want it to go away, but it'd be nice to have an alternative open source Android app catalog that's a little more liberal.
Gotcha, so very roughly speaking the same reason that people sometimes leave Debian for Ubuntu, because they hit the balance between ideological purity and convenience a bit better.
EDIT: Okay I did the Google search that I should've just done in the first place. Apparently they're not dropping Firefox fully, but rather forking it to "remove the proprietary binaries out of the official builds" (Google Play API, etc). I suppose APIs like that are important enough to your use-case that you need an alternative source for Firefox?