Nintendo were referring to features that would make Wii's successor unique when they said the console would 'surprise you', not its release date.
I don't think we'll see a successor to Wii anytime soon, but who knows, we might see a redesign.
2010 seems way too early for an entirely new console, especially considering the money and resources they have invested and are investing in 3DS. I don't think the company's capable of -or willing to- launching and sustaining 2 new machines within such a short span of time.
Nintendo aren't known for doing that, console-wise, but on the handheld front they have ample experience with redesigns. 
Considering recent Wii sales, a Wii redesign wouldn't surprise me. Also, it would be tiny, and include the newly-rumoured Wiimotionplus-remote thing, as well as WS and WS Resort. 
Nintendo Network ID: Cheebee 3DS Code: 2320 - 6113 - 9046
