Something I've been kicking around in response to The Ability Score Are Too Damn High.
In most of our ACKS games, we have had players roll five sets of stats, choose one to play and hold two as replacement characters. This tends to lead them to having the best of five.
An alternative I've been considering: roll a set of stats, 3d6 in order. Accept it as your character or reject it and reroll up to (say) four times. If your next set is better than what you rejected, too bad, and if you run out of mulligans, you play the last of the five.
I like this idea because it changes the problem from optimization (pick the best set of stats from the five) to satisficing (is this set of stats good enough?). It introduces an element of gambling, that OSR pillar risk and reward, that self-determination of "what is your ambition?", and of incomplete information. In the average case, I expect it would also accelerate the character-generation process; you probably aren't going to roll all five sets, and at while there are more decision-points, each decision is boolean (keep or reject). Characters will also in expectation have somewhat lower stats, which is also an outcome that I am OK with.
In order to preserve some amount of choice of class, and as a replacement for offstat-drops, I think allowing a player to swap any two scores in the set is probably reasonable. This preserves some input from the dice (for eg multi-primereq classes), but if you just want to play a wizard, fine, swap your highest into Int. And if you already rolled something high in your main stat, then you can shuffle around two of your offstats to your preference.