MMO worlds broken? Nay I say!

This mechanic (some mobs ignore taunt/aggro mechanics) works fine in many WoW fights, but they're not the rule. I can only think of one boss that ignores aggo, but that boss is a) only one phase in a four-phase fight, and b) can't one-shot anyone without telegraphing it far in advance, allowing people to get out of the way. Okay, maybe Onyxia as well during her air phase.

I'd like to address some of these.

Aggro: Asheron's Call didn't have aggro like the new games do. You attack something and it would attack back. Some foes would attack you for getting too close, and there were times that you could get foes to attack each other. Running between two groups and getting one to fire could, result in the other group being hit. They would then aggro on the group that attacked them. Virindi Executors were great for this.

There were also no true tanks. There were strong melee characters, but the foes would attack the characters that hurt them the most. One super monster had to be pushed into a wall, then pined in place by high def characters that didn't attack. The monsters would focus on the damage dealing mages and archers, but couldn't get to them because of the wall of melee guys just standing shoulder to shoulder. He had no ranged attacks, but his sword was basically instant death.

Static Worlds: Again from AC. There were world changing events. An insectoid race called the Olthoi invaded one patch. There were several underground hives that were level restricted. Until the hive was cleared, the Olthoi in that area made any real form of travel very dangerous. When a team was able to successfully beat a hive, that area was secure. The name of the players on the team that beat the hive would then be broadcast across the server.

In another case, there was a town that had become the gathering point for player trades. Congestion got so bad that the town was destroyed. Literally. A giant monster came in without waring and leveled the place. Years later it was being rebuilt but was still mostly ruins.

In yet another, one patch saw the addition of a statue in the center of every town. These statues would unleash swarms of living statues on the people in the towns, until the mechanism inside the statue base was destroyed. Again, this happened one time per town per server.

Finally, Dice rolls: AC didn't really seem to use them for combat. It used the FPS style of an actual projectile. It was possible to dodge spells and arrows by running behind trees and zig-zagging. Some spells were able to track a little bit.

Button Lock: Melee weapons had a slider that ranged the attacks from weak and fast, to strong and slow. The problem was that there was one attack.

Spells had no recharge, and could be cast repeatedly with no effect other than mana drain.

Now, AC was not without it's faults. Since there was only one attack, it was possible to set it to auto fire, and it would attack target a until it was dead, then move to the next foe that attacked, and so on. As long as there was stamina to use, the player didn't actually have to do anything. Mages took a great deal more effort to play and took a very long time to develop. Your choices were either Fast and boring, or tedious and powerful.

The problem with AC was that every character had the potential to be a tank mage. My axe fighter could self buff with a full set of level 6 (7 was highest then) spells. A level 1 character with a full set of buffs and a pocket healer could go from level 1 to level 20 in under an hour.

I had a thrown weapon character (Considered the worst of the three ranged weapon sets) that could go into a cave and spend a full 45 minutes in one spot, attacking non stop as hoards of Olthio rushed at me to die. I wasn't uncommon to be under attack by 20 or more critters at once while solo.

That became the norm for the game, and a progressive cycle of making harder foes, then giving more powerful tools to beat them went into effect. Eventually the line between veterans and new players was nearly insurmountable.

I'm a little late to this party, but I'll post anyway

The game already supports all the tools it needs to make fights more interesting, and little or no code needs to be written to accommodate it (although backfilling previous content might be a little tedious). Quantums and Voids are AT specific enemies that spawn at about the correct rate (once or twice per mission), the same could be done for other ATs.

The mechanic for summoning reinforcements without messing with spawn proximity already exits - Rikti Communication Officers (And Clockwork Dukes (or princes, whichever summon)). They open a portal, reinforcements spill out. A similar mechanic could work for some other groups (skyraiders "teleport" in as a summon, Tsoo ninjas "drop" from the ceiling, CoTs can summon the MM pets, etc)

Other mechanics that could be used to pose a difficulty for certain ATs: Have a minion/lieutenant that summons singularity, or that even justs casts repel - most melee heroes will have a problem, most ranged wont. Have a minion that has a mag 20 hold (long recharge). If a tank taunts without looking first,they may get held. Have more enemy healers and buffers. Have a minion that can cast a long duration debuff like the kind you can get from a lab reactor. Depending on how individually challenging/annoying these various ideas are, they could spawn with almost any group, or they could be more like quants/voids and only spawn once or twice a map.