I’m not sure if this is still true, but it was in the past.
The NetBSD installer used to get confused about partitioning if one was trying to install a new NetBSD system on a disk that had previously contained an installation of some other system like OpenBSD, FreeBSD or Linux. This was on MBR partitioned disks the last time I ran into it. The simple solution was to zero out the first 1000 blocks of the disk before attempting the NetBSD installation at which point everything worked smoothly.
If this is still an issue it may be even more difficult with a disk that was set up using GPT as it takes more than just zeroing out the first few blocks on the disk to totally wipe out the GPT setup. It might be nice to have an option in the Installer to “reset” a disk to an acceptable state for a NetBSD installation.
As for the packaging system, it has generally gotten more difficult to do a simple installation of packages on a new NetBSD system now that the package system supports so many other systems. In the old days packages were built and maintained for a particular NetBSD release. Now the package builds are in quarterly archives designed for building and installation on multiple systems. That’s nice because it greatly expands the number of people working on packages, but the downside is that the quarterly archives are not all built from source on a regular schedule so the package inter-dependencies can get all messed up. An update in one package may cause installation issues for other packages that depend on it and haven’t been rebuilt in the archive. I guess there are multiple solutions: 1) doing a regular rebuild of everything in an archive, 2)having some utility that would check for packages that are no longer installable from the archive, 3)building packages yourself which takes time and computer resources.
Pkg_comp is a nice utility for doing the third option. I have updated documentation on how this can be done such that a user need only build the packages they’re interested in installing on their system I contributed that documentation to the WiKi some time ago, but I’m not sure it was ever accepted and posted.