Interesting encounters do not have to take longer than trash mobs. They just have to be, well, more interesting. They can have low HP or be quick to kill, but with better tactics or gimmicks than just charging straight at you. One can look at Bungie combat encounters for an example of how to do good mob encounters.
I cut down a ton of my original post, since it got to the point where I felt like I was either going to rush it and not describe my thoughts accurately or spend all night working on it. Now I kind of wish I hadn't, but I actually wanted to have dinner and maybe play some GW2 tonight.
I ran through a bunch of different genres and described how enemies are treated as obstacles you must overcome and not speed bumps on the way to loot. Mario's Goombas, Halo's Grunts, etc. are all 'fodder' enemies, but they're not 'trash'. Their placement is such throughout the entire game that you encounter them once or twice alone, and then in greater numbers, with other enemy types, in different environments, etc. A grunt in Halo can still kill you if they have the advantage, which any good game will constantly give them.
Maybe the most notorious enemy in all of gaming, the Medusa Head, is utterly simple; it floats up, it floats down, moving along a sine wave in a single direction. But that's all it has to do because it's placed in such a way that it can destroy you if you're not careful. Then it appears with other enemies, or in locations that make it difficult to avoid or destroy them. Not many games are content to be hallways and rooms where uninteresting enemies just hang around, and those that do (coughcallofdutycough) are usually considered sub-standard. But they're the gold standard in MMOs.
I think the biggest reason for that is the community, which has basically pushed developers to make dungeons quick, easy and rewarding. You look at a dungeon in WoW from Mists of Pandaria and it's basically hallways with bosses at the end, whereas 10 years ago you had something like Blackrock Depths. If you introduced a dungeon like that into an MMO now, heads would explode. Here, I made a visual;
Exhibit A:
Blackrock Depths, circa 2005 (left), Gate of the Setting Sun, circa 2012 (upper right), Simulation of player reaction, circa 1981 (lower right).
There's no reason we can't have "Trash Mobs" in an MMO that do interesting things other than it slows down players who just want to get loot as quickly as possible, and because MMO developers are constantly working on the game after release
and interacting with the community, there's a constant push towards the lowest common denominator. "This is why we can't have nice things" and all that.
Obviously Guild Wars 2 is not immune as the dungeons have been brought down quite a bit since launch (AC Story especially). I will say, however, that they stick to their guns much more often than, say, Blizzard, who seem to kowtow to their official forums on a regular basis. But then again, WoW is popular for a reason and I doubt very much it has anything to do with
difficulty.
Of course, then you get those who just want to charge straight at the mob and then complain when they die because the AI outplayed them.
Yep.
Dungeons need to have scripted but evolving encounters so that entering the same dungeon twice feels totally fresh. This is something not currently possible in MMOs (yet).
I'm imagining a "difficulty adjustment" system that aggregates a number placed on each character and selects an appropriate difficulty for the party and changes mechanics based on that difficulty. Characters that have been running for a while will drag the difficulty up, which means they need to slow down and explain this is the "harder" version of the content a newbie in the group would see, and the rewards would alter based on that. If the newbie succeeds in helping and not dying, he gets the rewards the same as the group. If he doesn't, he gets his base level rewards he would have gotten if he entered with a full group of newbies. Win/win.
More randomization, more diversity in dungeon size / scope (I would be in favor of a new type of dungeon with a special designation that indicates it takes longer to complete). You don't need any kind of complex difficulty adjustment system ala Fractals, just more diversity and unpredictability. If players have to run something multiple times, each time should be at least a little different, right?
Actually, while we're on that subject, Fractals are a
great example because most of them aren't filled with trash at all. Only the Dredge and Ascalon fractals really spring to mind, because the others (Cliffside
especially) give their 'trash' purpose, if they have anything that even qualifies as trash. I think when we get new or revamped dungeons we'll see less trash and more encounters or events between bosses.
Ugh. Didn't want to do a Mega Post and I ended up doing one anyways.