According to that interview, in this thread, you'll be able to have 10 characters.
Only restriction is you can't have alliance and horde on same server.
So my question is: Are you going to use all 10 characters or will you save some for later expansions?
Me, I'm using 5 and that's it. Rest will be for expansions.
And since the professions are limited to 2, are you going to create alts to do all the professions?
And the servers will support 2500-3000 players. That seems a tad low, but it works for me.