Yes, summer is coming fast, and if you're a student interested in software development and engineering, Eclipse is a great place for a Summer of Code !
New ideas are still appearing on the wiki page and no doubt you'll get many more in a few weeks. Let me highlight some of the cool subjects you might apply for if you're interested in modeling.
Let's speak about EMF Compare, we tried to focus on cool stuffs as that's what open source is about.
First, the 3D visualization ! Using EMF Compare, the GMF Diagram support and GEF 3D, one can imagine to get a nice "time machine like" visualization of the model differences. One can easily imagine really nice representation using that third dimension, we have to display two (or three) versions of a diagram annotating the diagram elements with graphical hints saying "that's a new element", or "this one has been changed", so 3D can make sense here.
Second : huge models comparison , by huge we mean really huge like millions of elements. EMF Compare uses an heuristic-based algorithm to compare two models, while doing so its keeping processing data in memory (more important the models are, the more memory is used). The subject is two folds : first design and implements a MatchEngine needing less stuffs in memory, then leverage Eclipse technologies like CDO or JCRManagement in order to break the memory bound ! That may seems trivial, but when you need to process a lot of data, many parameters are changing.
Third : improving the "Graphical Compare'" proof of concept initiated by Tobias (flash demo here) .
Many more ideas are available and looks really cool especially in the modeling area, so If you're a student, jump and meet the Eclipse Community !