I feel RT was just turning the corner in all aspects of his game most notably, his pocket awareness before he went down. There is no reason to believe, a healthy RT cannot pick up where he left off.
On the Marino comparisons, Dan was blessed with among other things, great offensive lines that kept him relatively clean. However, he also helped himself quite a bit by making quick reads, quick decisions and snapping that legendary wrist of his. I suspect that the game will slow down for RT and you will see the most improvement in the aforementioned critical area where Dan was so masterful. I feel good about RT because, he's had an outsiders perspective of the position watching from the bench, QB meetings, and individual film study for almost 2 yrs. Mind is refreshed, body has healed, and by what I've seen he looks jacked.
Another thing, some of us forget is that the Dolphins were almost always one of the least penalized teams in the entire NFL for almost an entire decade. We did not beat ourselves with stupid penalties. Dolphins' have been the exact opposite in this area since RT's been here. You can't expect a QB's winning percentage to be exceptional with a mountain of TEAM inflicted wounds. QB success cannot be sustained with drive killing penalties and Defenses that can't get stops.
I do believe with the right ingredients RT can lead the Dolphins to a Super Bowl win. Too many equally skilled QB and certainly inferior QB's than RT have done it with the right mix of talent and the perfect amount of luck.
Let's see what happens...