PS. BTW, is there any reason Emacs is not already part of GSOC?
GSOC projects to improve Emacs have happened in the past. IIUC, the main hurdles are finding interesting projects that fit in the short timeline, and finding mentors for such projects. For example, several years back there were a couple GSOC projects to push guile&emacs integration: https://www.gnu.org/software/guile/news/gsoc-guile-emacs-and-emacsy.html