To the OP I have to say the video of Gannon was spot on. His body motions and movements, his running style, everything looked just like Ryan. The difference is that Gannon had an AMAZING OL to throw behind. He had a lot of room to step up and his throwing motion was never bothered. Maybe one day we will have that for Tannehill.
Now for the differences, Gannon was MUCH more accurate than Ryan is now, but Ryan has a much faster release. Gannon had much better weapons but this year we will get to see what Ryan can do with a few more than he had last year. I will agree Gannon is the type of ceiling that we should be hoping for, and patient that we are 2-5 year away from him having a chance to get to that point.
As for the Jake comparrison, I don't see it AT ALL. Jake was bi-polar or something. He would be playing great and suddenly start throwing straigtht to DBs for no reason. He didn't remind me of Ryan at all in any of that clip. Ryan is VERY careful with the ball and rarely throws into traffic. Well under half of Ryan's picks last year were picks he threw to the other team. His picks were balls batted up at the LOS or WRs bouncing the ball up that hit them in the hands. Once our WRs got used to how Ryan was throwing the ball we went the last 5 games with just maybe one or two picks.
I have to say the comparison to Gannon is pretty spot on. Of course he is much better than RT is now, but he sure looks just like him on the field. Nice job. Lets just hope he turns out that way.