I'm not denying the possibility. We even see two Davids in one of the viral promotions for the first movie. That isn't my complaint. My complaint is that I see it as gratuitous and potentially very silly to have two or more Davids in the movie. It's just Fassbender awkwardly talking to himself at that point. It also seems desperate, in that most reviews praised Fassbender's performance, so the studio says " Let's have two Fassbender's in the next movie!!!!"
It's like having two Ripleys.