It appears a big reason why Nintendo hasn't been able to announce any release dates for the Wii U is due to the FTC still hasn't approved of the device to go on sale since they cover anything electronic. A few rumors are leaning towards an October release with the possibility of November if the FTC delays the approval a bit longer.
http://www.egmnow.com/articles/news/...th-government/
Wii U Pro controller also revealed to have digital triggers which might make playing certain Gamecube games a bit tougher unless the clickable sticks are used to help replicate certain actions.
http://www.screwattack.com/news/wii-...gital-triggers
Nintendo also confirms any titles bought on the Wii's Virtual Console will be transferable with previous rumors stating Club Nintendo accounts would play a big role. It also confirms rumors of Nintendo going towards an account-based system for the Wii U in terms of games.
http://www.screwattack.com/news/wii-...console-titles
Finally, Sony commented on the lack of Vita stuff and PS4 news by saying they don't feel the need to discuss anything about the PS4 until they feel like it. They also are refusing to have a price drop on the Vita and they didn't plan to use their conference to discuss Vita games besides a few quick announcements.
http://www.screwattack.com/news/sony...ita-price-drop
http://www.giantbomb.com/news/sony-o...nference/4203/