Any problem of the MA must be dealt in a way which sets a new standard where everyone could reach a compromising point and be more or less content to play in it. The arena should stand as one. Any kind of "solution" that rips people apart and divides groups to form separate arenas, is highly unrecommended.
IMO, separation of arenas means that AH has failed to come up with a compromising point that effectively deals with different types of players on a mutual basis.
IMO, it also means that AH has failed to integrate the huge numbers into a single gameplay format, and thus has no choice but to go the "reverse" course and bring back the "Smallville" days of AH.
Essentially, it means that since AH cannot come up with a real "Massive Multiplayer" game format featuring 500~600 people in a single arena, it will just revert to the old days of small arenas by making 3 small servers with 200 people max --- man, that's just really sad thing to think about.
ps) The DA, TA and SEA is a special type of arena suited for limited purposes, and the CT is more of a small scale 'experimental' arena(which unfortunately seems to be failing)
ps2) The ToD might be fundamentally different, but we'll have to see about that.
There's a chance that the introduction of ToD would in effect, become something like "Arcade arena" and "Sim arena". It's pretty hard to imagine how the numbers might shift around, but if the new ToD becomes a huge success, the ToD might very well become the "main theme" of AH.
But at any rate, ToD and MA is more than just 'sim' and 'arcade' distinction. It wasn't meant to be a solution for the MA problem - it's a totally original project which HT and co. have been thinking for a long time, IIRC.