I play Eve online. Let me say that I have 26 million skill points in there. Thats about 2 years of skilling up. Some skills take 45 days to train. Some skills take a few hours or a few days. This all happens whether you play or not.
BUt, don't think Eve has no grind. The money is what you must grind for. IN eve, where your ship blows up, YOUR SHIP BLOWS UP! And, most the little awesome bits you had on there too.
But! Dont dispair, that is what makes pvp so awesome in EVE. You actually stand to loose something that means something to you. Trust me that people dont engage in pvp lightly but when they do it is hardcore and furious.
I also play NWN1 persistent world: Escaped from the Underdark. I have mentioned this is several other threads so I wont drag it out. It is not massive, but it is multi. about 15-40 people on usually. Heavily RP oriented, no real grind to speak of. If your character dies in pvp it is permanent death. I often go through about 3-6 characters a year there. Each one is a fully developed person and the whole experience is very immersive. THERE IS NO GRIND TO SPEAK OF, you can get to a high level in a couple days of playing.
I have lots of ideas from an mmorpg that has no grind. Without a lengthy explanation take for example a popular game on our forum: Haven and Hearth. Take out all the clicking to build things, ALL OF IT. Make everything have timers so that you may wait hours or even days for them to complete. Players build their cities and battle each other, it would become more about management than resource gathering or button clicking. Over-simplified but still get the point across i think.
BTW, check out NWN1, trust me it awesome if you are in the right persistent world. Check out Escaped from the Underdark if you can. Cant recommend these folks highly enough.