I never thought Dak was any more than he showed in the field the last few years. That's why it was necessary to invest in everything around him, interior line that they have neglected, a solid center to back up and take over in a year or two, guards that are young and worth a shit (Tyler Smith should be at tackle already and Tyron moved out or moved over), and an offensive scheme and game plan to get the most out of what you have. A bigger running back with some power and juke would be nice, too.
Then you have to figure out how to get consistency out of the defense. Dak sucks hard when the team sucks, but he can be tolerable when his supporting cast is awesome, which we haven't seen in a long time. If Seattle can look decent with Geno Smith, better coaching and more balance and consistency, Dallas could go pretty deep even with Dak and his limitations.
As far as contract, it's the NFL, and contracts are contracts. What looked monstrous a year ago looks like pretty average next year. And there's always another delusional team that will trade way too much for a washed up qb, like Russell Wilson.