MMO game philosophy for the last 15 years maintains that leveling content is a sort of long 'tutorial'. Its meant to show the very basics (and I mean VERY BASIC) of what is expected of you while not serving as a barrier. Understand that I don't really agree with this, I'm just pointing it out.
The way it used to work in Everquest and early World of Warcraft (prior to Lich King) is you would have static groups of mobs tactically placed in a way that meant pulling them was part of the challenge. In addition like you mentioned there were patrols that had to be accounted for as well so that you did not double pull.
But there were two roles available that have been long since omitted. Puller (was not always the Main Tank, frequently wasn't) and your Support/Crowd Control. Sometimes one class could fulfill both those roles, but not always. In 2.0 we had a minor use of CC with Repose and Sleep. I remember using them in dungeons like Wanderer's Palace, and even Stone Vigil. There was a few pulls in the latter that were quite devastating to tanks. Mainly the three mini dragon pull that could pull a fourth and the two sets of trio of ice sprites.
I personally would like to see the art of pulling come back and CC to become a thing again as well. I'm not opposed even to a fourth role of Support being added as well, with possibility of increasing group size to 5 or 6 to account.
The other issue there is with dungeon design is target prioritization. Other games have in the past used very dangerous mobs in groups that you wanted to take down or CC. Usually some sort of Wizard/Rogue type mob that could inflict high amounts of damage or inflict the party with debuffs or CC itself. Imagine if you did a Wall to Wall pull and one or two of the mobs would target the healer and sleep them. You would either want to burn them down first, CC them yourself, or be prepared to use a cure effect/potion on your healer.
Right now at least in Amourot they do have mobs that are slightly more dangerous because of AOEs they do, but telegraphed ground based marker AOEs are easily avoidable.