So far there has been a lot of speculation as to who Zoom truly is. A lot of people believe that his identity will reflect that of his comic book counterpart, Hunter Zolomon, who we've also been recently introduced to. I've been mulling it over quite a bit and I have come to a very different conclusion.
(photo courtesy tvline.com)
In the comics, Wally West becomes the second person to wield the Speed Force. There are a lot of difference from the comics canon and what's canon in the show. I have reason to believe that a lot of those differences are exactly why Zoom will be none other than a future version of Wally West.
(photo courtesy screencrush.com)
Here's my theory on why Wally West will become Zoom. SPOILERS.
(photo courtesy screenrant.com)
Speed Addiction: So the basis of this theory relies on how heavily speed force addiction has been referenced recently. Jay Garrick, The Flash of Earth-2 has already been addicted to Velocity-9 a serum that temporarily allows you to harness the Speed Force. Jay revealed that his addiction was in fact the reason that he lost his powers and not Zoom. Now this is a stretch admittedly but bare with me: A future version of Wally West's Flash becomes addicted to the same Velocity-9 serum Caitlyn is working on. Instead of taking his powers and killing him, it makes him the monster that is Zoom who travels back in time to steal a less experienced Barry's powers just as the Reverse Flash did.
(photo courtesy thefandom.net)
Casting Choices: I find it to be a little too much of a coincidence that one of the most terrifying voice actors of our time; Tony Todd, happens to be the same race as the character most likely to become the next person on Earth-1 to be able to harness the speed force. That was a long ass sentence.
(photo courtesy usatoday.com)
Family Ties: This is probably the biggest reason. Wally West is the literal son Joe never had while Barry will always be the closest thing to the son he's always wanted. This has already been skimmed over in previous episodes and it's probably going to be fleshed out way more in future episodes.
And there you have it. That's why I think Wally will become Zoom. Let me know if you find anything wrong with that theory and when it comes to pass, just remember you read it here first!