It is taking long and this is one of the few things I don't like about xenforo. When you install and addon or theme users get a blank page during that time. I find this unacceptable. But it is nowhere near 10+ minutes. Something seems to be wrong with your config. I have 2 languages, 5 themes, and 10+ addons and it takes 1-2 minutes at most which I already think is very long.
We have run into some servers where it just seems very slow. I'm not sure if it's CPU or I/O limited in those situations. (My laptop, with a reasonable CPU but horrible I/O seems to handle it ok.)
The number of styles and languages will have a direct effect on the speed. The less you have of each of those, the faster it will be.
The blank page is annoying, agreed, but there's nothing that can be done about it unfortunately. To stop the blank page would require the rebuild to be done in one page load, and that obviously can't be done if it's going to take 10 minutes. (Via the command line, for example, isn't a problem.)
Really, on a production board, the issue shouldn't be coming up too often.
It's taking about 5 minutes on my boards, which are currently all on the same server and very minimalist installations (almost zero customisation, only 2 or 3 addons installed). This is a shared hosting server running FreeBSD, db is on a separate server.