In this particular model, those services and physical locations that can and should be shared--green and leisure space, libraries, dormitories, refectories, work-study, etc.--are. In other words, it does not become the burden of any one denominational college to build and maintain a library, 50 acres of sporting fields, or a student union, or to operate a student work-study program or financial aid office. The cost for those elements is shared. College and university consultants say that there's a minimum enrollment under which a college on the standard model (the departmental model) risks financial failure. The number typically given, except in cases of massive endowments, is 1,200 students. The larger potential student body size of the "university of Christendom" model can help ensure the flourishing of each college by allaying some of the financial pressures against success through sharing the cost of facilities. A shared refectory, library, and dormitory space (consider the cost of building several refectories, substantial libraries, and dormitories for under 500 students apiece), not to mention green and leisure space, removes the full onus from the back of any one group.
Does this require confessional compromise? No. The charter of such an institution would be drafted in such a way as to allow each denominational group to flourish in a pattern that accords with its own confession. In essence, the "university of Christendom" model can be thought of as an "academic town." Just as a Lutheran college today uses services provided by the town in which it's located--water, for example, trash removal, even the interlibrary loan services of the local public library--so in this model would each college use the academic town, as it were, of the "university of Christendom." The only difference is that a "university of Christendom" would provide services more germane to the residential and academic nature of the "town": room and board facilities, library facilities, student union, green space, certain student services, etc. Each college would be responsible for its own requirements for graduation and maintaining its own chapel and whatever else it deemed conducive to fostering its particular confession.
What the model requires is the coming together of several groups within "orthodox" Christianity to find land and build buildings. Upfront challenges include discovering such groups and garnering their interest in the project; success in meeting these challenges, however, promises a substantial reward, which is the implementation of denominationally orthodox higher education that might not be or is not otherwise available. Furthermore, macro academic departments can be created across the university so that a philosophy department will not be comprised only of the, say, 2 Lutheran philosophers on the campus, but of all the philosophers on the campus, potentially affording students a richer educational experience.
Weaknesses in this model include: the potential for the erosion of confessional standards; tension in values over certain shared responsibilities; the proportionately larger initial start-up cost (although this would be shared); agreement, with other denominational groups, on the geographic location of such an endeavor (Lutherans and the Reformed are predominant in the Upper Midwest; but what of other groups whose population centers are to the West, East, or South?); the difficulties--and threat to institutional integrity--that could naturally be experienced if certain financial burdens are disproportionately borne by one group or another.