Yeh, I think 'sequel' was just a poor choice of wording on their part, not a literal sequel to RuneScape.
Regarding their quote about RuneScape:
QUOTE
...We've tried to keep the emphasis on storyline and interaction between characters and players. We try not to encourage level grinding or anything else like that.
Hah, I couldn't disagree more with him there. The only storyline you get is fed to you in tiny pieces through quests, all of which are fairly unoriginal and the least bit engaging. Then when you finally get something interesting it
never gets resolved. I remember back in the day when Jagex made a big thing over their "amazing multi-part plague city quest series"; now we have so many loose ends I honestly can't remember the last time I did a quest that gave me a satisfactory conclusion. Indeed, there's an underlying theme of the Gods in RuneScape, but it's scarcely touched upon in any real depth to be considered an integral part of the 'plot'. I suppose what I'm trying to say is, if anything, the storyline has been one of RuneScape's weakest points in my opinion.
Then there's the level grinding... Well, they may not 'encourage' it, but it's there, and it's what keeps the players paying even if they don't want to admit it. It's the part of the game that people would refer to (knowingly or not) if they say they're 'addicted' for the simple reason of a guaranteed sense of accomplishment. If you grind for long enough, you're going to get that next level. There's no probability, chance or luck involved, it's just good old fashioned repetition and knowing that in the end, you'll get what you're aiming for. Whether that's good or bad, fun or not, is a different matter entirely.
Anyway, went a little bit off topic there, sorry about that.

I suppose I'd just like to think that they'll do things slightly differently with MechScape, rather than letting it turn into another story-less grind-fest.