Cases? Stands? you mean more just to buy? more junk to drag around? more junk to find places to store?
Netbooks have everything they need in one handy device, no add-on crap required.
However, tablets are way sexier, just not as practical.
Where I see multi-touch tablets being a huge play, if the game companies are smart, is by replacing traditional multi-player games with the tablet.
We even play checkers and chess on my Android phone :)