Their buffs are fine for their level range. They came out at L26 and L31. So their stats were the best at L26 and 31.

It's like comparing a Season 1 pet like Malison to a Season 3 pet like HJ, and then asking for malison to be buffed just because it has lower stats. It's like gear - the pets eventually outdate, but just slower. And the percentage stats are implemented to make pets last longer!