The PS3 is the same way, you can transfer your PS3 account to another PS3 but you can only do it a limit number of times. It wouldn't make sense to allow multiple devices per account, you'd just get people installing their games on their friends' consoles (like happened in the PS3 early days when they let you have your account active on 5 PS3's at the same time).
Well, I think it's just the concern that you have no actual account security and that everything you do/purchase is (for the time being) permanently tethered to the box in your lounge room. It puts a physical ball-and-chain on your digital expenditure, which can be perceived as illogical given the nature of digital content. Less so about sharing accounts, moreso about knowing that at the moment there's literally nothing you can do. Account sharing isn't really an issue, as you could simply have accounts only active on one console at a time.
As it is, Nintendo doesn't even offer in-house profile/data transfer. I'm positive this will change, but it's still annoying. Under the current system if you Wii U were to break, or worse yet get stolen, there's zero way to recover your data and content. Account level content fixes that, both for yourself and Nintendo.
I don't really want to drag this thread into that discussion though, just noting that there's rationality behind disappointment and insecurity with how Wii U accounts are currently handled.
What
I'm interested in is if anybody has done performance tests for HDD versus disk? Probably not, given the system has only been out a little over a day, but playing via HDD with the Wii provided a very obvious performance boost whenever it came to loading. The Prime series is a good example, as data had to load every time you used a door.