In order to get a perfectly installed system I always have to install it twice: first to find out how much goes into /usr (and other filesystems) and then install it for a second time with a suitable partitioning. To solve this, wouldn't it be nice if Anaconda would first let me chose what packages to install and then do the partitioning? Because only after having made my package selection, I know how big /usr should become (blocks and inodes). Solaris8 already has such a feature... BTW, setting the numbers of inodes on a filesystems is often more suitable than running a journalling filesystem because fsck will be fast anyway with only a little amount of inodes. So another improvement I would ask for is to have the (optional?) possibility to configure #inodes/block-size/etc. in the installer as well...
This is very difficult to do because on low memory machines we need to have swapped turned on before we can load the package information, and we can't turn swap on until after partitioning.