You never played WoW's harder content if you think EQ has/had more challenging and engaging gameplay.
I was a part of several top guilds in WoW. I did all of WoW's harder content from launch through WoTLK before 99% of the population did. The dungeon and raid
boss encounters were and still are more difficult in WoW. I quit when they started watering the rest of the challenge of the game down.
WoW 5-man heroics in TBC were pretty challenging content. I remember terrible groups would wipe in them all the time. Nowadays, you just chain pull linear dungeons, AOE tank and AOE kill without effort with random people from random servers.
Once you got to WoTLK, trash became absolutely trivial. Which was dumb, because you'd still have to clear it. It's not fun or engaging when it's trivial. Just feed me the more challenging boss encounters.
Pantheon is definitely going for a less barebones approach to boss fights, they even showed off a full fledged one in the latest stream. If we can get that good mix of the difficulty of EQ1 and the difficulty of WoW like in said boss fight, the content could be really interesting.
WoW isn't a bad game. In fact, it's a great game. The best the genre has had, and probably ever will. It just became something much different. It's just not what people who are interested in this game are looking for anymore. Needed to be a healthy medium like WoW originally had, but now the game is too far gone. MMORPG kind of loses it's luster when the content is consistently trivial and the game world is more game than world.
I want to have to set up pulls, have difficult time CC'ing, face resists, pickup adds--the need to adapt on the fly. I don't want a controlled environment where there's absolutely no danger or challenge.