This all reminds me of when Squaresoft made Final Fantasy Mystic Quest for the US market, thinking it would sell better because americans wanted dumber games. It didn't work and it's a pretty much forgotten game in the FF series.
I understand today there's a pretty big market for casual gamers, specially after the advent of Wii and Cellphone games, but I think it's a big error to try to make adventure games for this market. It'd be a smarter move, IMO, to try to attract people who don't necessarilly play video games, but are inteligent and like to flex their brains solving puzzles. I really don't think intelligent people are becoming extinct.
So, what I'm trying to say is that adventure games shouldn't aim the Wii Party market, who'll think it's all too complicated anyway, nor the modern console gamers, who finds this genre too slow-paced. They should attract a new audience by having really funny or thought-provoking stories, great dialogue, and good puzzles. And that means not dumbing down the experience.
What needs to go so as not to push newcomers away is the big amounts of frustration some old games used to have, and again that won't be achieved by dumbing down things, because that'll just ruin the experience, but to have logical puzzles and a good hint system. If you're getting too frustrated, it's much better to have the game giving you hints, if you want to, than stop playing and go looking for a walkthrough.