Well i feel i should add a few more of my copper coins to this article:
I think that the people posting here are looking for a more 'roll'playing experience (although i can't be sure) so the combat would indeed be very hard to manage in play-by post. A way to fix this, or atleast increase the speed slightily, is to have more than one adventuring group in the world, each run by its own GM, and having few characters in each group, no more than 3 or 4. Also, the players and GM would be arranged in groups according to the time they post in, to have as similar posting times as possible. This way, we kill MANY birds with a single stone: We can have a many more players and GMs in the same game world thus accomodating more people withought needing a 'waiting list' or somesuch, we can have the game go faster because there are less players per GM and more similar posting time, AND the RP value of the game increases by alot, since we would have groups and not just players intereacting against each other, and that could even lead to very nice situations like one group consisting of evil characters against a group of good characters and yet another group of neutral characters in the middle, thus removing the need for 'mastermind villain' NPCs and other such rivals/helpers in many cases, simply because there are enough players to compensate for some of them.
Of course, that last part about interaction between groups would probably create complications and slow down the play somewhat, but since it would be uncommon for two or more groups to be in the same event at the same time (the villains would build a fortress, then leave, then the good guys come and clear it, so the groups dont have to directly interact, unless there is an actual battle between both groups, which would be rare), and also the players would have different GMs giving them (most of the time) quests unrelated to other players, it wouldnt be quite a big problem.
Please DO comment on this, I like to have other people's opinions. Also, dont forget this is just my opinion, no need to actually follow any of it.