It's really not as complicated as you are making it...
The offensive staff, read OC Shawn Watson, wants a QB that is quick / fast enough to elude the rush and buy time in the pocket to find an open receiver downfield. In seeking out this kind of QB they realize that there will be times that the QB will have to take off and run. All they are looking for are QB's that can buy time or take off and run and turn a "bad" play into a good one.
Well Watson better coach them up good in being able to avoid the rush because when NU plays the better teams that can easily shut down our average WRs, they'll be scrambling.
If the Robinson kid had committed I would feel much better about the direction this offense would be evolving into. (IF Watson bolts, Gabbert will as well)
Face it, NU has had 2 WR's drafted in the NFL in the past 20+ years and BOTH were QBs (Newcombe, Crouch). Even with Cally, Watson and Gilmore pimping the WCO to potential recruits, still nada.
As to the speed thing, my opinion is unless you want to run a spread option offense (which we don't), the less your quarterback HAS to run, the better. Little Gab has enough of a motor to break for ten if a gaping hole opens in the pocket, and he could elude pressure and occasionally run the zone read. From all I've been hearing and reading, Watson was high on him because he has good mechanics, he's a solid game manager, and he can make most any throw.
But let's not fool ourselves. If Tyler plays much at all it isn't going to be four a couple years, assuming Green is still our QB of the future. He could develop a lot between now and then. I'm pretty sure Watson wouldn't read these posts about a dual threat QB, put down his coffee, and go, "Well sh#t. I didn't think of that."
That's the problem, right there. NU for all intensive purposes has no reason not to be running a spread option offense based running attack. You see Oregon, similar to NU in regards to recruiting grounds, flourish year after year running this. See Utah as well. Finally Florida and it's plethora of talent in the sunshine state takes this offense and in 3 years at helm, Meyer pulls down 2 MNCS.
Don't you not see something fundamentally wrong when Florida is running this offense and NU is running a pro style??
This offense, the NU offense, is NOT a good fit for NU.
I'll be anxious to see what Old Balls (Snyder's) offense looks like at KSU in the coming years.