Entirely fair.
I've finished a playthrough now and I do have to say the exp curve is a bit of a pain point still like it tends to be in gen 2.
I tried to maintain a 5 mon party and was 15-20 levels underlevel going into the Victory Road rival who promptly sent me to a grind session, at which point I just memory edited in rare candies... This was despite going out of my way to defeat trainers for exp.
I'm not sure if anyone has figured out an actual solution to the GSC level curve yet, so that maybe can't be helped.
I will probably be doing a playthrough with a smaller set of main party mon sometime soon.