Short summary of my personal opinion on jets QBs:
1) If healthy, mark will be no better than he has been in the past. He is what he is, a bottom 5 nfl starter.
2) if healthy, Geno should replace mark by midseason. It will likely not result in significantly more wins, and will most likely be viewed as Rex trying to make a last gasp effort to save his job. Unless Geno is wildly improved in the next 8-10 weeks, the offense is still likely to be pretty bad.
3) who cares about the other QBs? The jets may carry as many as 4 if they want to see the backups fight it out (as the also bad 2000 patriots team did) but realistically every qb on the roster not named Geno is unlikely to be on the 2014 team.