That was really really bad. Not even the teasing but just conceptually a bad episode. I'll let them slide on the math being off because whatever. But this big bad scary villain in this future timeline:
Does nothing for months at a time up until he kills Iris. Breaks Wally's spine. And then he's free for 4 MORE YEARS and accomplishes nothing. Doesn't kill Barry or the rest of Team Flash or destroy Central City.
Entire episode in a future timeline to establish that Barry is friends with Cisco, loves Joe, and should believe in his team. Nope, never done that before. It might've had more meaning if Team Flash was fractured in the present timeline, but they're fine.