I'm not sure having 2 QBs in the backfield (if that's what you are suggesting) really gives you that much more than you get with Taysom + a running back. Put 2 QBs in and you someone else has to sit down (either your RB or a receiver). With Taysom you already have a dual run/pass threat. The problem in defending a dual threat QB is that might run it, requiring your defense to step up and stop the run, or he might throw it, requiring your defense to stay in coverage. Forcing the defense to make that choice is what puts pressure on the defense.
Adding another QB while losing a RB or a receiver doesn't really enhance the dual threat you already have with Taysom. You just lose another offensive option.