Another thing we lost was the amount of trials, we got less of those as well.
Most of their ideas had potential that was let down by their poor implementation. Potd as an example could have been great if the room templates varied in shape and size with things in them and perhaps the chance of special rooms, perhaps even change so that what unlocked the passage was not only killing x monsters but could also be finding a key or helping an npc with something so they unlocked it or some group based puzzle, perhaps if not all of it was underground, secret rooms where extra treasure could be found, random mini bosses that could drop some loot for the group if killed, change the current traps for ones that could be disarmed or in other ways dealt with. The idea of potd was never bad, it simply never lived up to what it could have been.
In HW we gave up more then we got, and like you say the dungeons was of lower quality then in ARR... or perhaps they just felt that way to me. Especially the 3.5 dungeons that to me felt like the worst dungeons in the game, they felt uninspiring and boring to the point where I can count on one hand how many times I did them. Less is only better if the quality is higher, but here it has just been less is less with lower quality.