Honest question....do you have any stats to back up the supposed "unacceptably high number of drops"? I haven't seen any.
And, where is it accepted that you only want 4% passes dropped? I think 1 out of 12 is a pretty good number just on the face of it....,..but you're saying it should be 1 out of 24 balls thrown. That'd be great, but is that really the average or target number you're realistically shooting for?
I went back and watched that Arky game and I had to search for those drops, one of which was by AK on a swing pass......it wasn't like we were dropping a lot of balls that night, at all.
Ideally speaking, you'd want to average a little less than 1 drop per 24 passes.
It's really not that hard to wrap your head around if you think about it. Of any 24 ball thrown you can expect 30-40% not to be completed (with good QB play). So (rounding up) that's 7-10 incompletions of 24 passes if you have good QB play. Of those, you can expect a few to be defended, a couple uncatchable passes, and a ball or two thrown away. What you can't afford to have is nearly 1/10 of your passes thrown be drops by receivers on catchable balls.
It's hard to find stats for CFB and comparing the college game to the NFL game isn't always the most productive of pursuits because the level of play is much higher in the NFL. However, the passing game in college, generally speaking, features larger passing windows and schemes and rule differences friendlier to the passing game, so I think this is a situation where you can compare the two, like you could for, say, completion percentage. What's bad in one league is bad in the other, too.
That all being said, 8.3 percent would have been dead last in the NFL last season in drop percentage by more than 2%. The best percentage was ~2% and the median was right at 4%.
Granted, I'm not sure if that percentage would hold steady over the course of the season (the Arkansas game might be a fluke, though I imagine our season drop percentage was probably somewhere between 7-9% based off of nothing but personal recollection, which I will admit is flawed and unreliable), so the point would be moot. But generally speaking, if your offense is dropping more than 5% of the passes thrown, you're not getting good play from your WRs.