Mobs in Maps at endgame vs early game

On my way up to t15s i noticed significantly less mobs in red maps then yellow or white. It feels like patchs are thin and spread out with higher life but they do less damage. This incentives me to just skip the mobs and do leagues mechanics and boss and port out. In yellow maps and even Trans white maps the screen was filled with mobs. Did you over tune mobs density reductions in end game to assume that we would be juicing every map to the fullest to get a normal map feel? Or am in a patch of just poorly designed maps? Maps also seem to be very repetitive like all cnotes here all Jac l hive here not alot of actual variety on the atlas in function