Kid Icarus: Uprising maybe delayed till 2012 in Europe. The news comes from a post-E3 event held in the Netherlands, where Nintendo site, N1ntendo managed to get their hands on a new fact-sheet for the game. According to the printed date, it is now planned to be released during Q1 2012 in European territories. Despite the potential delay, there are no reasons as to what’s caused it.
The intention to include an online mode was mentioned recently by Masahiro Sakurai, so it's possible the game may have been delayed to further develop the feature. There's no information on whether the game has been delayed in the US