I foresee a potentially important problem for the pay-to-play model :
Should the first game be considered free, and every subsequent game is paid, then the vast majority of players will limit themselves to one game at a time.
I recall that there were several games going concurrently near the end. I for one was playing 4 games concurrently at one point (ouch!).
The natural consequence to limiting oneself to one game at a time will be an increase in the number of idlers and bailers. Why continue to play a game if things are going sour, and in order to play another game you would have to pay to play? No, I predict most players will simply stop playing their "free" game, and then opt into a new game instead. This will of course exacerbate the idler/bailer problem (which was already an issue), and spoil many a game for those who are doing well.
So yeah, I can't see how paying for any number of games will foster a growing community. If anything, it might destroy it quicker than ever.
The challenge, as far as I can see, is to somehow mesh the web and client communities into one. However, that doesn't seem to be an option (yet). Another possibility is to mesh the already viable LT community with the GT community. United we stand, and all those platitudes.