So, the Jets acquired Tim Tebow, while keeping Mark Sanchez; and they plan to play them both, picking their starters on game day...
They're on crack.
If you're going to go with a two QB strategy (a stupid idea in general, but there are certain specific situations where I suppose it MIGHT work), you want to pick two players whose strengths and weaknesses offset each other.
In Tebow and Sanchez, they've got two players with basically the same weaknesses and strengths.
Tebow doesn't have a field read, plain and simple; and most of the time neither does Sanchez. Because of their inconsistent read and feel, while they both have natural leadership abilities, they can't consistently be a leader on the field, able to rally the team to a greater performance than they otherwise might have achieved.
THAT is what is needed to be a great quarterback. Not arm strength, not accuracy, not scramble, not just plain natural talent... There have been plenty of first round draft pick quarterbacks who have had all that, and just couldn't make it in the NFL, ending up as busts, or just middling talents (or most frustrating, the "almost" or "coulda been" greats).
Leadership, situational awareness, game feel, and instant read, are what separates great quarterbacks from good ones.
Brady isn't great because of his arm, he's great because of his field read, and because of his on field leadership.
The instant field read is what lets Brady know when he CAN hold it for what seems to be WAY too long (especially behind a mediocre pass protect line) and still make the long yardage pass... or when he needs to dump it off. The leadership and game feel, are what lets him take a team that's down, disorganized, demoralized... Rally them up, and come back and win.
Tebow doesn't have it. Sanchez sometimes shows a little bit of it, but sometimes he's clearly in his own head, or he just doesn't have the situational awareness.
Both of them are still playing college ball; and playing college ball in the NFL is a good way to become a legendary draft bust.
They both try to use their footwork and toughness, to get out of trouble. They both alternate between dumping off too soon, and missing major opportunities; and holding on too long and taking a sack, a down, or a short pitch where they could have had 10 or 15 yards if they'd seen the earlier opening.
There were some great QBs who just had that read naturally from minute one (Joe Montana, Dan Marino)... But most guys had to learn it. It can sometimes take years, but most of the really great guys pick it up pretty fast ONCE THEY UNDERSTAND WHAT THEY'RE DOING WRONG.
Drew Bledsoe could have been one of the greatest quarterbacks of all time. He had an incredible arm. He threw long passes and quick pitches better than anyone playing with him... But he had inconsistent situational awareness, field read, and game feel. It made him one of the most intercepted QBs, and one of the most sacked QBs (in 1994, his second season, he threw more passes than any other QB had in history, was fourth in touchdowns, but also first (or last) in interceptions).
But he could have had it. You could see it in pressure situations when he wasn't overthinking it, and wasn't second guessing; he was just reading the field and responding fluidly... And he got the Patriots into the superbowl with it.
November 13th 1994, week 11, with a 3-6 record; the Patriots are losing to the Minnesota viking 20-3 at the half. Bledsoe comes out of halftime in two minute drill, firing left right and center, going 45/70 with no interceptions, leading the the Patriots to win the game 26-20 in overtime. In one of the greatest full season comebacks in NFL history, the Patriots then go undefeated the remainder of the season, basically running every game in two minute offense, trying to salvage the playoff chances for the first time since 1986.
The problem with Bledsoe was, he didn't have a strong enough coach/management team to break him of his bad habits, and get him out of his ego, show him what he was doing wrong and make him work to change it.
This isn't to say that Bill Parcells was weak, far from it; but Parcels wasn't allowed to discipline Bledsoe properly, particularly in his first season under old owner James Orthwein. Bledsoe was allowed to become a "superstar", and was handled too gently.
After buying the Pats from Orthwein, Bob Kraft gave Parcells more leeway to discipline Bledsoe in his second season, but not enough, and by his third season the pattern was set... he wasn't coachable anymore (Bledsoe is why for all his subsequent contracts, Parcells insisted on having full control and leeway over personnel).
Thus, Bledsoe may not even make the hall of fame, never mind be in anyones top ten lists (except maybe top ten "could have been an all time great but wasn't" list).
Tebow and Sanchez both need some really great coaching. Tebow in particular should respond well to it... But not if they're splitting duties with each other. They both need the kind of individual attention and focus that only comes with experience at being the starter, and the leader on the field.
Both are salvagable as potentially great quarterbacks... but not in this system.