I've used Solaris quite a bit and the default /tmp in ram behaviour ends up meaning that a lot of things that should be put in /tmp end up elsewhere because it's just too easy to run out of ram.
as others have noted, /tmp shouldn't create that much I/O as most of the files don't actually need to hit disk. However, since ext3 is so badly behaved in the face of fsyncs, this is not the case on ext3 based systems.
but instead of changing how the system works, they should switch to a different filesystem that doesn't have the bad behaviour of ext3. Use either ext4 or XFS