room versions are incompatible naturally and room takeovers were a bug. So saying it's the cause for these things, is misleading.
At this time there are 9 room versions. Once the room version had to be incremented because of a bug in the consensus algorithm, which required a new algorithm, i.e. room version.
That's it. Bugs happen when you create new tech...
> Except of course for censorship-resilient public rooms where it shines, which goes back to my point that "decentralized rooms" as an XMPP extension would have made sense.
There are many more reasons for wanting decentralized rooms, e.g. autonomy, reliability, availability, anti-takeover - and it works for private rooms as well.
Prospectively, it enables things like P2P and multi homing
I would never want to go back to the XMPP like it is today. And XMPP today is not Matrix, even if you could turn it to Matrix, but what is the point of doing that? Matrix is already there!
If you want Matrix to be an XMPP extension, I suggest creating a new XEP pointing to spec.matrix.org and call it XMPP v2. No idea what you would gain from it though.