I wouldn't be surprised if uninstalling Groovy-Eclipse could address some of his problems, but the post shows a larger problem with the IDE work we are (or at least I am) doing. Too often features are implemented so that a handful of vocal users are happy, but the silent 99% don't have their needs fully met.
As a simple example, consider this statement: "Sometimes, selecting a launch configuration
with arrow keys and hitting enter twice to run it works. Sometimes, it
runs a previous launch configuration. Using the mouse is fully reliable
but less efficient." I'm pretty sure it's because sometimes he has the editor active and the expected thing runs, but sometimes some other view is active. This makes sense to power users and the behavior is consistent with the rest of Eclipse, but it is probably non-intuitive for new users.
The problem is that determining and implementing the most intuitive workflow for new users that doesn't annoy power users is not a cheap or easy process. It involves something like user studies and active engagement with all of the community (not just the 1% (no, not *that* 1%)). I admit that this is something that I have failed to do enough of.