Debconf/prioritity=low is just the same as 'expert'. I have no idea why it is called debconf, as it actually seems quite unrelated. (It was not documented at the bootprompt, but only in the installation guide.)There is an option you can pass to the installer to set the debconf priority I believe. I think it is even documented in the boot prompt information. If you set it to low it will ask all questions right from the begining. Len Sorensen
Anyway, it does not really matter. Overall the installer is quite nice, and works well.
The area of biggest concern is the partitioning which sees rather disorganized, presumably a side effect of tring to create a good cross-platform solution that works well. If and when a graphical X-based installer mode is created it may be nicer to use qtparted or something similar for the partitioning.
Again this is just a set of overall comments, and not complaints or note of a real bug,