Sanchez is a pretty solid backup at this point in his career (I can't believe he is already 30).
If you take away his name and just look at his numbers, he is a serviceable QB with a winning record. That is hard to do in the NFL. He has a better winning pct than Cutler, Cousins, Cassel, Kaepernick, Bortles, Tannehill, and Bradford. Just think, he is now the winningest QB on the roster with 37 career wins. That is more than Glennon+Shaw+Hoyer+Barkley combined.
So I don't know how this makes us worse. If anything, we added some veteran presence to the QB room.