Syncing. All installations/updates/whatever are done on the main server where they can't break languages, then the arena servers are synced with the main one.
That's one reason, yes. For compiled interpreters, I actually had to take one arenas out of rotating, pull, compile, test, put it back in rotation, and repeat the process for the remaining arenas servers.
Now I just pull, compile, test, and sync. Much simpler.
The biggest advantage is that I do not have to rollback any changes that cause problems. The affected language is simply blacklisted and not synced until the problem is resolved.