What adventure I would like to see on Wii? Grim Fandango, as it´s the only LucasArts adventure (besides Monkey Island 4, which was already ported to PS2 years ago), that I can´t play on PC via ScummVM.
But let´s forget LA, they won´t port any classics, let alone develop new p&c adventures (I´m sure the new Indy game will be an action adventure).
Regarding newer adventures: Similar to DS, only Japanese developers will develop p&c adventures directly for the Wii (see Z&W, Another Code). I hope an Ace Attorney episode will be done some day for the Wii.
Unlike Japanese companies, western developers will always use the PC as their development system for this genre and we will see more decent ports on Wii with Sam & Max 2, Runaway 3 and others already announced. I hope nice games like Jack Keane and A Vampyre Story will be ported as well, but don´t except western p&c companies to choose the Wii as their original development platform.