What do you do if your controller breaks or you have a faulty battery or screen or something? Think about it.
This is something they need to listen on and carefully consider before they next show the console. It's not a deal breaker for me, but if they NEVER allow multi-tablet use, that's really short sighted and limiting for limitings sake IMO. I would accept worse graphical output for multiplayer games that used multiple tablets. Realistically I would probably only buy one extra tablet, so I want 2 player option minimum at some point in the consoles life.
If they're not going to have good local multiplayer using these things, then they DEFINITELY need a good online solution. Its always felt to me like Nintendo were a last bastion of local multiplayer gaming -- yeah I play some FIFA and some co-op on 360 and PS3, but the 4 guys in a room having a laugh, that was still Nintendo's ground... they can come up with all these quirky asymmetrical multiplayer ideas to keep it alive somewhat, but the inequality of it taints it. This feels like the end of local multiplayer on home consoles
I need to see Wario Ware on this thing btw. I bet that'll be great.