Store workspaces list in a shared location
The list of used workspaces is stored in the Eclipse ConfigurationScope - so it is shared between all workspaces using the particular Eclipse instance. However the list is limited to five items and it is not available for i.e. a new Eclipse installation. This can be improved upon.
Many users probably don't know but the length can be extended. I set mine to 99. Maybe recommend increasing the value and/or just increase it silently?
Yes, I was thinking of just silently increasing the value. In retrospect I think it's a bad idea. I don't want to mess with the settings, so what you're proposing; recommend to change the value, is probably the best solution.
Well, I wouldn't care if it's silently increased. Frankly, I started to dislike dialogs prompting me for obvious things - especially since I started using OS X. It's probably sufficient to just document the behavior as a given.