Considering the high-ish price and Japan being handheld country, those numbers can hardly be considered bad or even concerning. Outside of the PS2, it's pretty much in line with every other successful launch. But as the Vita showed, the first week (or even month) hardly matters in the grand scheme of things, so what happens at the start of January and beyond is really going to be a lot more telling.
Honestly though, none of the numbers we have seen so far are concerning outside of the UK report. I think Nintendo hits its 2 million mark before the end of this year, with close to another million alone coming for the US and Japan during December. The 5.5 million mark for April seems a bit hazy though, and I don't think they have the current Q1 software lineup to meet such sales numbers. But so far, all the gloom and doom on the numbers we currently have seem to be fueled more with personal taste or ignorance (IMO) then the actual "bomba" of the WiiU.
As for NintendoLand also being a "bomba" in Japan; it is hardly a title you can judge on first week sales numbers such as a Resident Evil 6. It shall be interesting to see what kind of legs it develops in the coming year.