Re: Why does wget output go to standard error?
AFAIK there are three std*'s stdin, stdout and stderr.
I can only guess that choosing stderr for regular output was done so as not to interferen with the progress output which is directed to stdout I presume.
If you are interested in redirecting the output, you needn't be aware as to where it redirects to normally. Just use the or command-line argument as per the documentation link you provided.
Never upgrade your working system to the newest release without thorough testing on the actual hardware you will be running it on.
Never perform a system update in a live session
Installed Ubuntu Touch 1.0 on my Nexus 7. And loving it!