I am against it.
I would rather have the current Game Editor be updated in other areas. Even though the Nintendo DS is a great device it's just not feasible for small developers.
I'd rather see Game Editor being pushed on current platforms. For instance making use of DirectX and so forth on new Windows Mobile devices (if it already does that, then I'm sorry, it's just an example). Or even move to XNA on Windows. That would in theory even add the ability to export to XBox360 devices.
If other devices are to be added then I'd rather go for Symbian phones than the Nintendo DS. For small indie development, this is most likely the way to go. However I think that hobbyist game developers will prefer the DS.
Also, rather than new platforms I'd like to see added functionality within Game Editor. Game Editor is great because it can export to so many devices. It does lack some simple things which will make life easier though. Such as getPixel(), variable width bitmap fonts, and such things. I don't know if GledPlay has proper sprite rotation. Such advances in Game Editor will excite me more than to be able to develop on a Nintendo DS. I am also looking forward to the multi-player addition. That's going to be great.
Well that's my little bit.