He threw for less than 50% completion percentage. The Bronco wins were above average, but Tebow's play was no where near above average. The reason he had late game heroics is because he put his team in a bind every game by being a below average qb.
Flynn has one game as a starter, lets let him start for Seattle before we judge him as a successful starting guy in this league. As far as Hasslebeck. In '98, he was only on the practice squad, so time between him and Favre were limited that year. After that, I would give more credit to Holmgren (who he followed to Seattle) than Favre.
I really don't think that starting QB's spend a lot of time "training" their future replacement. What good does that do them? They are busy keeping their job. The best mentor situations are when a veteran is a young guys backup, imo.