What HTC MAY be doing could be ingenious.
Here is a way to upgrade the Game Engine, thereby satisfying the owners of higher end PCs, while keeping the original AH with the same game engine to maintain the current subscriber base.
It's a great business decision if this is what he's planning.
Think about it. And I know he said "Undecided" but we can speculate, so relax.
You get the newer players who want the eye candy. You get the players with the higher end machines. They pay their $15.00 a month, and get the mission arena.
Then you keep the original AH as is, the players with older machines keep paying their $15.00 a month.
Boom. You've got a whole new game, and you grow your subcriber base.
Maybe a compromise would work. (I know, more speculation)
$20.00 a month, access to both arenas.
$10.00 a month, access to original AH arenas.