It's not just Cyrodiil. From what we can read here, it's a lot of dungeons, for example. Yesterday I had a hard crash while fighting a harrowstorm in The Reach, so even overland can crash the game now.
Error 307 booted from server twice now just trying to do alchemy. Recommended action is to wait 15-20 minutes to try logging back in. (Because it wasn't letting me back in right away at all.) Then five minutes in-game, then booted again.
Guildie was booted 8 times in about an hour earlier this morning. Awesome.