After months of watching we are really no closer to knowing who zoom really is. Plenty of theories exist, Barry E2, Henry Allen, Jay even Joe West has been thrown out there. I want to take a minute to throw another explanation out there.
First let me start with why i don't think its Barry, Henry ect. Grant Gustin has came out and in no uncertain words said it wasn't Barry E2, but not far off,and well get into that comment in a minute. Now as much as i think it would be awesome to see john Wesley snipp in costume again...he hasn't been around enough in this season to make an emotional impact..and that's usually how these things work...big reveal with big emotional impact. Same with Jay, if he turns out to be zoom there's no real emotional impact except maybe Caitlin..sure it would hurt the team but their all not really close to Jay.
Now for the meat and potatoes...why i think zoom is future Wally west. Zoom claims to be and so far has proven to be the fastest man alive. Wally had a far greater understanding of the speed force and was indeed the fastest man alive. He could also borrow speed much like zoom. Now in the last episode wally spoke of how he wanted to be an astronaut just for the speed..so his lust for speed is established. Now picture this...Zoom is future E1 wally, he's already been kid flash, the flash, saved lives and fought many battles. But in all this had never been held at the same respect as Barry. We know from season one the flash museum is coming...so wally does all these great things and never gets a museum or a key to the city...and on top of that feels as though Joe always accepts Barry as his son and not him. It drives him crazy and he decides to not just be the fastest man alive but the only fast man alive. It kinda makes sense with Grant's comment..."not far off"...wally is a flash just not the flash we know yet.
Just a theory...now get off the soapbox and tell me your theories....who is zoom??