I tried to upgrade an install of Fedora Core to Fedora Core 2. The root partition had 433M free but the installer told me I needed 322M more disk space. This means it wants to use an extra 750M of disk space for FC2 vs. FC for an "upgrade". It makes me think it is installing packages I don't already have and probably don't want. It would be nice if the installer would allow the user to review the packages selected for installation like you used to be able to do in the RedHat 9 installer. The option to review packages selected for installation doesn't have to appear on screen by default. It could be made to appear only for an expert install mode.
It's intentionally not there. The only things we do on an upgrade are * Upgrade versions of existing packages * Bring in any new dependencies needed. There are a few special cases, but those are heuristics based on things previously installed that don't have Obsoletes for various reasons. Adding a review button won't let you really change anything about that.
I'm not asking for the option to be there by default just that it is there for those few occasions when I or others (ie. FC developers verifying the automatic package selection) might find it of some help. I would expect that an upgrade should only upgrade existing installed packages plus any new dependencies that the newer packages require but I fail to see how such an upgrade should require 750 Meg more than was already being used. If I could review the package selection I could review or possibly alter the list of packages selected for install. It would also allow me to see a package I may no longer want/need and remove it before doing an upgrade to save space.