I'm not making the rules, and I'm not sure of my views on asterisks for other changes.
I happen to think this a major rule change that will and would have affected a great many players' numbers, and some not so much.
I think Papi's numbers would have been even better, perhaps much better had they changed the rule in 2000.
The fact that Aaron played longer and got more PAs does matter, but it's not related to anything the league did. You can make adjustments for shorter seasons, on your own.
One can always look at HRs per PA, but how can you adjust, even roughly, for things like the shift being taken away?