I think you're right, Dust, in that Gizmo would easily hold the record in kick return yards if his team had been scored on more often. His average return was certainly good enough. I don't remember Eric Blount being all that spectacular.
I actually went onto TSN and they have all the statistics for return yards. It really is just a matter of him having more returns than anyone else, he has a very good 25.8 average. He has 56 returns, his closest competition is Dorsey who has 50 returns with an average of 25.1. Stefan Logan his teammate actually has a better average, albeit in a much smaller sample size of 8 returns.
I do actually recall Blount having 1 good year, other than that I think he was average at returns.