I don't think elusiveness or speed matter at all, although others will disagree with me. Nobody really knows the answer unfortunately. You will get a bunch of guesses and anecdotal evidence based on small samples that don't rule out other variables that may or may not have impacted the #s.
I think the position you assign the blitzer from is just as important as attributes. Dbs haven't been as effective in the role in my experience. Mlbs have had better results than OLBs for me. This is all in the 4-3 and nickel. Others may have different experiences with different formations, or the same ones even.
I personally think ath, str, and GI are most important along with strong formation IQ, but I don't know anything for certain. I have had players lead div 2 in sacks, but who knows why that happened. I have had players put up great numbers as underclassman only to develop further and have their numbers drop as upper classman. Strength of schedule? Talent around the player? Time of possession? I couldn't say.