He did have Dave Krieg for a season or two, didn't he? I wouldn't categorize Krieg or what he achieved over his nearly two-decade long career as mediocre. I agree with you for the most part on the others, but Dave Krieg has to be one of the biggest overachievers at QB in NFL history, he went to three Pro Bowls in Seattle in his 12 seasons there, was their franchise's all-time leader in wins, career TD's and passing yards until Matt Hasselback and Russell Wilson showed up in the 21st century. Sure, he got sacked a lot and had a bit of a fumbling problem but being that he had small hands and that some of his O-lines during the 1980's werent the best, you'd likely get nailed too quite a bit.
I have always had a preference for overachievers, not just in sports but life in general. Their work ethic, attitude and determination and focus is usually 4-5x higher than those around then with more natural, professional skills in business but don't always apply themselves fully. I believe God put overachievers on this planet to remind or warn those of us with higher IQ's, intellegence, natural capabilities and overall skill sets to not slack off or be complacent and apply themselves accordingly.
Dave Krieg was one such person and although he never played a down for New Orleans, I've always liked him and had a deep, admired respect for him as a player and Seattle Seahawks were very lucky to have him as their starting QB for nearly a decade.
I also put Rod Smith of Denver and our very own Marques Colston in the same category and part of me strongly believes that if Colston had finished his career with 1,500-2,000 more receiving yards, he might fall into that "borderline Hall of Famer" category list.