1. Jameis Winston and Marcus Mariotta came out as juniors and played well as rookies. Dak played four years, through his senior year. While Dak was not graded as highly as those two, there is no reason to think he can't be as successful with a better offensive supporting cast.
2. This was not a Super Bowl roster. Nor did the FO treat this as a Super Bowl team. They made no significant free agent moves. And used a high 2nd round pick on a redshirt player. Losing Romo may have cost us a shot at a division championship and maybe a playoff win, but that is all. So let's keep that in perspective and enjoy the glimpse of our future in Dak.
3. This is a great reason to change this offensive playbook. Last year, it was proven again that no other QB can succeed in this Garrett/Linehan system other than Romo. So, if this coaching staff was smart, they will tailor the system to the player (Dak), not the player to the system, and change this system for good. We have the personnel to turn this offense in the SEA offense: run-first, play action passing, lots of rollouts to keep the pass rush guessing, read draws to open up bigger rushing lanes for Zeke. I would love to see this transition.
4. If Dak succeeds, Romo can be a premier backup. I know he (and some here) won't want to hear that, and his contract is probably un-cuttable until end of next year (in 2017, he has a cap hit of $24M, but dead money of $19M, so only a $5M savings; whereas in 2018, he has a cap hit of $25M, but dead money of only $8M, so a $17M savings). So, if Dak proves capable, keep Romo around to back him up through 2017, and cut him in 2018. Or trade him, if you find a willing contender.