that's my entire theory about Syrio being alive, as well. He would have to be one of the faceless for it to be true. Either he sneaked away never to be seen until whenever, is actually the Jaqun Huguerre dude, or--this is nuts--actually killed Meryn Trent and just decided to walk in his shoes this whole time.
I don't give a dick about Syrio, honestly. His character was nothing special to me and I'd be fine if he were dead. I just happen to think that he could very well be alive.
Hey, I was right about the Lannisters actually being in debt--based soley on my hunch that most of the wealthiest people are actually either in debt, or flat out bankrupt; and that would actually be a real reason to ally with the Tyrells. People chided me for suggesting that because "the show has spent innumerable amounts of time telling us that the Lannisters are the wealthiest in all of Westeros!" So, it takes a 1 minute scene from Tywin to inform us all of that, and suddenly all of the rest of you are like "Of course!"
I bite my thumb at these people!