fwiw I loved every bit of dialogue in Deathspank, Brutal Legend, Psychonauts. It's just the gameplay in all of them was not that great (Psychonauts was the best of the 3 though).
I don't think there's any worry as to the writing. I just hope they have real gameplay design skill for the game part. Even an adventure game takes talent as shown by the lack of it in all those 2 or 3/5 star games reviewed on adventuregamers all the time.
The length is another major issue imo. If they design it as an XLBA/PSN type game, I fear it'll be short and small in scope. If this thing hits $400,000 quickly, I think its shows that they can get the money to do a full Grim Fandango, Kings Quest, Gray Matter length 10-15 hour adventure title with full size scope.