Preform AV existed before achievments were even considered (since 2006).
Just my 2 cents.
That saying I got my Battlemaster (mostly soloed, sometimes with 1-3 friends) without using such addons for achievments.
Sometimes you will face people who completely have no clue, no gear or bot and even things like AV Perfection are doable then.
As for the change - no idea if it's good or bad, time will tell.