There's been enough lessons-learned from the current MMORPGs so that hopefully they will get past the initial problems they all seem to have quickly, and get on to the content.
Until someone proves they have learned these lessons (and the ones from Diablo 1 & 2), don't bet the kingdom. There's the POTENTIAL for Blizzard to learn from these lessons, but "potential" is just a French word for "you ain't no good yet."
Diablo 2 had a lot of potential. It lived up to some of it, but not as much as I expected. I only stayed with it this long because nothing better came out. I am probably going to break down, soon, and get Jagged Alliance 2, and that might well wipe D2 off my screen, for a while at least. JA1 was the top of the heap for turn-based tactical squad combat, and I'm feelin that itch again, after all the real time but rather simplistic Diablo "challenge". The only dis I heard of JA2 was that it "got too hard" toward the end. Worst case for me: can't play it "hardcore", and end up reloading from saved games after fatal mistakes. I only held off because I was having fun in D2 with hardcore chars, and playing team variants. D2X... does not quite have the same thrill, I'm afraid.
And see, that's the thing. JA1 is a PROVEN commodity, a top-ten of all time for me, and the JA2 demo offered more of the same essence. I thought that War3 was going to be the next stage in that development, with role play and strategy in one package, but apparently not. By contrast, what has Blizzard got to show us as PROOF they can handle a morpeg? Realm security for D2 is NOT good. Once duping showed up, it has not gone away. If they close down one or two methods, more open up, just variations on a theme. D2 game balance was largely "OK", but they took huge strides backward with LoD in that department, and the whole thing of rushing the product out the door, pooh-poohing any need for outside testing... the arrogance of that and the fiasco results will soon be erased from my memory.
Lessons learned from other morpegs? Hardly. The PROBLEMS have been discovered. No solutions have yet materialized. That comes up short, in my book, of what defines "lessons learned".
One more thing. I'm an NFL fan. I grew up in the DC area, so the team I'm fanatical about is Washington. They had a dismal preseason, just dismal. There was a lot of speculation, and some hope (and some prayer) that the dismal preseason wouldn't mean a thing. That come regular season, we'd see a different result. Well, today was opening day, and the team got thrashed 30-3 by the team who had the worst record in the league last year. This... is not a good thing. Just because the preseason pointed out the team's weaknesses does not mean they could translate into fixing them. Defining a problem is only the beginning of the lesson.
Usually it really IS as simple as, what you see is what you get. And what I see in Blizzard North right now is a company who pushed their product out the door before it was ready (so much for THAT slogan. I'll never read it again with a straight face). They would not test. They dabbled in fan feedback just enough to screw things up worse, but not far enough to make much of anything better, and they ran a slipshod public test across multiple builds, relying on feedback at random, when they DID test. Feature creep ate their game, and yet their chance to show us they can learn the lessons of their mistakes was... with D2X.
As fans, we can still hope. But come opening day of the new WoW game, can they shake off these preseason disasters and produce a stellar product? I'll believe it when I see it. Trust is a fragile thing, and once broken, sometimes it can never be repaired.