Preference import has another major issue. (which I had hoped back in the days of Eclipse 3.0 would have solved).
Export / Import of preferences is an all or nothing proposition.
If you, as a developer, have a core set of preferences you want to set, but are happy with the rest being at default, then you cannot simply import just those preferences you care about.
If you hand edit the preferences export to only have what you care about, start a fresh copy of eclipse, and import your preferences, you now have a bad installation of eclipse. Time to start over.
At 2 companies I worked at, we implemented our own Preferences layer to Eclipse just to work around how much of a PITA it was to maintain Eclipse preferences.
(Many felt Eclipse Preferences were harder and more obtuse to maintain than the MS Windows Registry)
We had the following layers, in order of how they were resolved, before being applied...
0) Eclipse Default
1) Corporate Baseline
2) Project Baseline
3) Developer Specific
4) Project Mandated
5) Corporate / Legal Mandated
Layers 1 thru 5 were deltas (only those entries deemed important)
Layer 1, and 5 were obtained daily from a known set of URLs
Layer 2, and 4 were obtained from the project scm tree, and updated on each checkout/pull
Layer 3 was obtained from the ${user.home}/.eclipseprefs/ tree
Each delta handled the not only the normal preferences, but also many of the secondary preferences in delta form (like individual java formatter settings)