Massively

Okay...

Firstly...the game's only had one expansion released so far. Claiming that their 'expansions' are all 'more of the same' is...dishonest to say the least

Secondly...less casual and less friendly? WoW's still one of the most user-friendly MMOs on the market, especially in regards to system specifications. As for being nothing but 'raiding and battlegrounds' that's a problem with most MMOs in general with the possible exception of EVE...

Thirdly....precisely what do you mean by the interface discouraging interaction? Instancing? Welcome to 2008. Instancing is now an integral part of MMO-dom and is likely to remain so for the foreseeable future. And that most of the instances in WoW are dungeons that require a group and/or raid (y'know...interaction?). At any rate the community in WoW, or any online game for that matter, is what you make of it, instancing or not.

And finally...lots of MMOs are still chugging along after WoW's release...and once WoW's been surpassed I suspect it will still be chugging along as well. Neither UO or Everquest are particularly special in that regard.

Actually, the expansions ARE more of the same, with a slight twist. As are most MMO expansions. I am not saying it is a bad thing, but I am saying that the expansions are not changing the WoW gameplay system from what it has been. Leveling is a casual affair until you hit the end, in which case guilding and scheduled play is the way to truly advance. Yes, you can casually run dailies and farm for badges, however if you actually look at how much time it takes to get enough badges vs. how much time you put in raiding - it is actually much easier to gear up. Thus, casual = having a RL schedule, not how many hours you play. This type of gameplay remains the same, even in Wrath (so far anyway)

And yes, WoW is friendly. However, LoTR is also very casual and friendly as another subscription game. Then, there are a number of free MMOs supported by microtranactions (such as Mabinogi) which are FAR more casual and friendly. Some of them are downright made to hang out and socialize in. They are full of user interaction on a level that dwarfs WoW. Finally, MUDs (and incarnations) are usually VERY social and friendly, yet the text interface is far from casual or friendly. Still, from a social standpoint, they are far more interactive than WoW. Last time I tried a MUD I was greeted by a live person and made felt at home within minutes of starting.

Since EQ hit the scene, MMO interfaces discourage interaction. And this is what I mean - you talk in a chat box constantly that has no relation to your avatar's actual location. When, in WoW, was the last time you walked by someone and overheard an interesting conversation, maybe joined in? If I jump into some of those free MMOs, the town center is abuzz with chatter, bubbles over people's heads everywhere. Yet in WoW I would stand in Ironforge (pre expansion) surrounded by hundreds of players silent as can be. The only person speaking is a wandering NPC merchant.

Further, on interfaces not encouraging interactions - WoW is set up to run an instance or PvP. Nearly everything about the game is aimed at that. UO had spells, skills and gameplay lifted from MUDs (which have even more) that targets interaction, not combat. Seriously, in UO, is there a point to summon a pet? No, it is just for fun. How about when you changed your appearance? The only person your fooling is another player. Again, some of the free MMOs are full of gameplay elements targeted at person-to-person play as opposed to person-to-environment play. And thus, the WoW interface has developed into a window great for PvE or PvP, but not for Community.

Last, I am not saying WoW will die as in it will stop running. No, I bet WoW sits around for at least 10 years. I was using the term as in "killer" being a new game that grabs a huge market share like WoW and that becomes the game everyone says, "no one can touch X" At that point, WoW will have a sharp decline in subscribers, but will maintain for a long time.

Again, WoW's success is it's biggest long-term problem. I think the original gameplay from level 1 to level 60 is brilliant. Yet I also think that it only works if there is enough critical mass in those levels. Every alt I level in WoW is a chore, not because I am leveling again, but because I can't find groups due to the lack of people at my level. Everyone is at 70 or powerleveling through the early content. Even Blizzard is adding tools to powerlevel through! So what happens when the level is 80, or 90, or 100? As time goes on we get farther and farther away from that brilliant gameplay. So, in order to keep feeding us that feeling, the expansions provide that great leveling feeling followed by the raiding feeling we have come to expect, and WoW needs to deliver.

WoW is like McDonalds in a weird way. They serve an easy meal. If they try and serve something else, then their not McDonalds anymore. So, you stick to your recipe even if it becomes the same thing over and over. Then other MMOs, say Jack in the Box come along and grab millions of customers. now that company is stuck with it's menu. The only difference is that computer games also have to suffer from evolving graphics. So it is almost as if their food gets less tasty over the years compared to the new flavors (graphics) made. They can upgrade like EvE or spin off a new chain (EQ2)....

Anyway, I am off topic. The whole point of this is to say, again, it is not about money that will dethrone WoW as the best game out there, it will be content. Yes, often content = money and it is true that people will want a large world to explore. But a billion dollar investment? I believe the next generation of MMO that takes the throne will be an evolution of what we have plus a good solid helping of a new way of thinking. Like a MMO without levels for instance as one way to depart from the norm.