A good contract is mutually beneficial. If the Rams and St. Louis can come to an agreement that satisfies both of their requirements, a deal will get done. Since the lease terms were fulfilled completely, your question about comfort is moot. The Dome is in good condition, it's just not fancy. The CVC could have done more to make it better, but it never could be made top tier for significantly less than it would cost to build a new stadium. That's why they declined the arbitration.
I've been to KC, Tennessee, Chicago, Minnesota, Tampa, Green Bay and Houston and I can say that the Dome falls in the same category as these stadiums. I've also been to Indy, Seattle and Dallas and the Dome falls flat compared to them.