The major issue was the lack of any dramatic tension in the "is it real" idea. There's no reason this iteration needed to follow the Ahnold movie or the PK Dick story, so they could have done better with that. I was halfway hoping it really was all a Rekall fantasy. Although that would have been an aggravating plot twist, at least it wouldn't have been 100% expected.
I agree, that's what struck me after watching it. I guess if I had never seen the original...
Also, I can appreciate a movie wanting to not be a direct copy but I felt that "The Fall" and the "I Robot"s weren't much of a replacement for the crazy over-the-topness of Mars, Kuato, Benny, Michael Ironside and Ronny Cox, sticking probes up noses, midgets with machine guns and so on. Naturally, out of all that they keep the three-breasted chick but whatever....