DL is definitely a problem, but no one ever said this team was loaded. We have nice pieces and a superhuman QB that makes it all work at a high level. That alone should net him the MVP.
Unfortunately, you are correct with your concern. This D is not capable of consistently containing a high powered offense with a good RB and competent WRs. Without any semblance of a pass rush most playoff caliber QBs will have an easy go of it. Maybe Sunday isn't a true indication of what they're capable of, but it sure as hell didn't look promising.