It's really not as bad as it's being made out to be. They're doing just fine with the depleted weapons they have to work with. I think the Bills can get to the playoffs with either of the 3. They don't have to be superstars, just be consistent, efficient, and mistake free. So far, EJ is the only one with a TD pass in each game he's played in the preseason, Taylor brings excitement, and Cassel brings the needed veteran experience.
Best case scenario is still EJ winning the week 1 starting job as the long term answer at the position for years to come. 2nd best case is Taylor. Cassel is not the long term answer. He should be the veteran backup and insurance if EJ or TT falters, but from a win now standpoint, he'll serve the purpose.