Two things I *wish* Sun would develop for Solaris:
1) A root-style backup like mksysb for AIX. This makes the backup and reinstallation of the rootvg easy.
2) Get a good logical volume manager that is integrated into Solaris that allows for mirroring and unmirroring root disk on-the-fly, without the need to reboot. This is insane in today's OS world that Sun still requires a reboot to mirror/unmirror root, and also to boot off a CD to remove the disks from Solaris Volume Manager control. The AIX LVM is a marvel and so nice to work with. I can migrate partitions to other disks, if needed. Also, AIX has a defragfs command. As well as recreatevg and reorgvg, plus filemon and fileplace commands.
I find it amazing that more of the world isn't running AIX!