The change from 16 to 12 F seats on most planes has reduced the number of upgrades significantly. However when saver fares roll out the number of upgrades should increase since a percentage of elites will take the savings and be ineligible.
As for raising the requirements I'd say that would be bad. If anything maybe add a tier above 75k.
I agree - just add another tier on top of 75k that would naturally get even higher priority than lower elite statuses for complimentary elite upgrades. As a low-level MVP, I'd probably lose interest in being loyal to AS if the 20k minimum was raised as that threshold is already a challenge to meet. I'm also curious to see the effect of the new Saver Fare will have on complimentary elite upgrades.