As for 'Who's running the show', Jeremy mentioned another name :

"Actually, Mark is Chris's boss's boss - Rob Denton is Chris's boss. Mark's not directly involved in the day-to-day UO stuff at all. "

Mark in that context being Mark Jacobs, head of EA/Mythic, Chris being Chris Rabideau, who is currently director for UO and DAoC.

There was also a comment in the last town hall recording about there being somewhere over 30 and possibly 40 actual developers/programmers.