I voted for iPad first for many of the reasons listed above. And here are some additional thoughts:
1. Creating an intuitive UI for the iPad CAN and SHOULD be done. And we have a greater chance of success if we design it in tandem with the PC/Mac/Desktop experience (instead of retrofitting it later). And if we implement AirPlay technology, playing it on the couch on an iPad, through an Apple TV on the big screen would be awesome. Of course, the UI would need to work when you only have the iPad.
2. We need to design the art/graphics with high resolution displays in mind FIRST. When my iPad 3 gets here tomorrow, it will have a higher resolution screen than the computer I work on every day. (I'm a graphic designer. I design websites and mobile UI every single day.)
3. We have a unique opportunity to design an RPG from the ground up that takes advantage of a modern device like the iPad. Tablets like the iPad aren't going anywhere. They are truly our future, whether you like it or not.
4. I want to play this game. And if it's on my iPad, I'll actually get to play it. Spending time with my family comes first, as others here have mentioned. But when I go to bed at night, I can lie next to my wife and play Wasteland 2 for a couple hours before I fall asleep. If it's on my computer, I won't get to play nearly as much (or want to since I sit in front of the computer for 8-10 hours a day).
