The thematic clusters ideas have charm and potential merit, but it seems to be fraught with the potential for logistical nightmares re scheduling and cross-over. Adopt such a system ONLY if you are SURE such problems can be eliminated. I think that among whatever is required in the humanities, there should be a 3 or 6 credit portion that is dedicated to the arts. The history requirement should either be broadened in terms of what courses can count, or history should be folded in under the general rubric of humanities, in the same way that all of the different sciences are included in the general categoryof science. The core should include English, math, science.
Capstone courses are a good idea.
Certainly this should be considered within majors. A college-wide such experience would be valuable, if appropriately implemented. I suspect a college-wide capstone may be logistically difficult. There definitely should NOT be a Director, or Dean ,etc. for Gen Ed. Faculty should be used in the classrooms and labs.