It is already a rehash of series 1 if he isn't or is Zoom, so it doesn't matter. The series is holding my attention and the characterisation and acting is close to excellent, this all that matters for me.
It does strike me that while Earth-2 is an alternate earth with a different history and peoples, and therefore anything is possible storywise, the plot similarities might be suggestive of the truth of things.
Consider that on earth-1 Harrison Wells' life appears much the same as his earth-2 self, up until he is killed and replaced by the time-travelling Eobard Thawne who needs to recreate The Flash and will use Wells' planned Particle Accelerator to instigate an 'accident' that will do it.
On Earth-2 we are appearing to see what might have happened if Earth-2 Harrison Wells had lived. He builds a career and his Particle Accelerator explodes... but is this a true accident or did Wells intentionally trigger the event as Thawne did? If it is no accident then Wells has a plan for doing it, and how then does he know of the Multiverse?
So considering the story so far it is quite possible that whatever the earth Harrison Wells is destined for villainy. He fixated on Jay Garrick as an enemy, and there is history between the two, he is manipulative and intuitively assesses Barry Allens potential and knows how to exploit him in a similar was Wells/Thawne did - is it coincience that Zoom appears to share this gift for manipulation and using people to further his ends? Is it not noteworthy that Zoom appears not to be human, nor speak like a normal person? How could he end up this way, unless his appearance is deceiving and the truth much more complex than it appears?
I can believe that Zoom is some facet of Wells himself yes, but I can also believe this is an allegory of Doctor Frankenstein and his monster. Wells created Zoom, and he is living with that...
What if wells created Zoom from his world barry then, or maybe there was a wally west who became Zoom?
What if they need to find reverse Flash and bring him somehow back to defeat Zoom?