As far as speed goes... sure X11 lets you hash faster than Scrypt... but it is all relative... everyone is hashing faster. The big draw is the reduction on power usage and heat. Would love to see more coins head for X11 and less for scrypt.
Those big draws are an optimized miner away from disappearing, people will always trade more heat/power for greater hash. The problem with X11 is that it is still quite new so it is hard to say whether it will become a standard like scrypt or fade quickly like heavy once optimizers get to tackle it.
That said, the pool will likely get supported in the future but the priority was clearly on getting sha2 & scrypt up and running first.