I'd disagree with what is said.
I've never played EQ, so perhaps thats where it comes from, but, WoW was a huge leap in gaming from SWG
Issues with 'games' that I've accepted for the time, and won't instantly chance
a) World will be static, it may have some changing elements (eg SWG's new Rebel/Imperial's control)
b) You are limited to what you can see, but not limited to what you can imagine. If the world doesn't let you turn door handles, can't mean you aren't imagining doing it.
c) Games will have loopholes, you leap through them by your own choice, SWG had plenty, haven't seen that many in WoW. Some loopholes end you in a situation where any RPG is out the window
Now, for just those points
a) WoW hasn't moved forward much, SWG has started too, where a winning faction switches to controlling certain area's
Where WoW has moved forward is the 'sense' of accomplishment, you pass on notes to a new seciton saying "This guys helped out here, you might be able to use him", but, it still indicates where you are coming from still have a problem. Which is expected, you fixed something but the main problem is there, lack of army.
For the big quests where you go kill person Z, but afterwards, Z is still alive for others, just picture some new hotshot taking the place, you are not a 'hero' as such in WoW, merely a person doing tasks and heroic things, great, you overthrew Z, doesn't mean V wasn't ready to step up.
Just how you look at it and accept the short commings of a computer.
You could 'fix' the Defias problem by hiring players to continually clear the camps, thus, new players have no defias problem. Not exactly the point of the game though, its to continue on, there still aren't enough gaurds to keep the smugglers down, but you've done some good.
b) Goes back to A, you see Z die, killed him, but see Z still alive for someone else, or see their armies still around. Just imagine V's stepped up to the plate. You did a great good, but you're only one adventurer, or a small group. Not a king leading armies.
c) There's always that shortcut sitting there, you take it, you take the shortcut. If pen and paper gave you 10 wishes to get out of situations, and you take them, then the game losses its sense of challenge, well, there it is. Its just a person can cut off those shortcuts instantly if such a situation. a Game is much slower.
Overall MMORPG from whence I started have changed. They are nowhere near what the human imagination can accomplish, but for me with 2 kids and the inability to getout and get friends together nightly, MMORPG are in no way bad

. Which I'm sure you weren't saying.
For advancement. WoW has catered for the average gamer.
For 'graphics' or 'puzzles'
Walking into Uldaman's ending chamber, well, you can not stop and think about it, or you can look around, make assumptions, ADVENTURE. I've been in plenty of groups where we've looked at a room and had to stop and think about it. And plenty of situations to call for that.
Caves falling in around you, spilling out Trolls.
Statues being brought to life
Escorting people
Bombs being throw around
Alerters alerting people about
Finding items (books on tables that start quests, bottles on the ground)
All that can be built on and has been. All that needs thinking, but, its not a case of, oh, the caves are falling in, what do we do, as its real time, you have to work together and trust the other person as an individual, in Pen and Paper you would normally have the person next to you casting a spell, and no 'immediate' danger to yourself, so you have more time to collaborate or discuss. I think you include this in your problem solving problem. Well, in a game it can't be analyzed and solved, you have to react, and react differently to other scenarios where you can stop and think. If you do so, its likely you'll die in game. If you do with someone in front of you, you won't
Unless your DM says times up, roll now, roll now, roll now.
So, for puzzle solving I think you would have to exclude anything that involves something happening where you have to react.
MMORPG considerably different to other comparisons.
Only think of a puzzle where nothing happens at the start.
Would I like to see more of 'stop and pause' puzzles, sure, and I seriously expect I will.
I'm not sure about the Deadmines with the cannon, didn't do that part but I'm pretty sure you had to stop and put two and two together. It didn't tell you.
But I think you'll fine MMORPG are where you have to real time react, with a group. Where decisions will not always be passed to you to discuss. And you are on a story, a story that yes, eventually peaks and, pretty much the game ends.
For a MMORPG the story has to evolve. As they have gotten more complicated they have been bottled down with bugs that stop new content. But, from recent EQII and WoW, new content seems to be coming in enough. PLUS
You can always experience a new adventure in another MMORPG, if you can get over the fact that to enjoy the game, you don't need to be the peak level.
A sight often lost on players, who start the grind, then get disappointed at the end. When they should've been thrilled with the grind. And disappointed its stopped.