Another often underused component which has ZERO core heat exchange is the Component Heat Exchanger. All it does is pass heat back and forth between components, meaning that you can pass heat off to other components without risking altering the temperature flow of the actual MOX design.
Furthermore, each component heat exchanger can transfer 36 heat per tick. Now, here's some math for you:
Max heat transfer for a Component Heat Exchanger: 36
Max heat dissipation from an Advanced Heat Vent: 12
Number of sides remaining on a Component Heat Exchanger next to nuclear material: 3
3*12 = 36
Meaning that one component heat exchanger can keep things running smoothly with three advanced heat vents adjacent. Basically giving you 36 heat dissipation without otherwise harming the delicate temperature equilibrium of your reactor.
As a not-very-economical demonstration, I present the Heat Distribution Transfer Vector reactor. The HDTV takes advantage of this curious mechanic to handle a pair of quad MOX cells in a 3 chamber reactor. The 'excess' cooling is in the component heat vents, so it will not impact the overall core temperature.
Another interesting design concept is to incorporate Cooling Cells which are then cooled off through various means as a way of transferring heat from nuclear material on out without upsetting the balance of the heat in the reactor itself, although not in a CRCS setup. here is an example of this mechanic in practice.
Of course, I still maintain that the CRCS reactors are going to be the stars of this show. The Pocket Split DDoS reactor would only see an increase in efficiency and EU output from using MOX fuels at high temperatures, with zero additional drawbacks, and with NR's being more economically viable, the old Alpha Pocket DDoS reactor might get dusted off and re-commissioned into service. Or, for those of you who can handle the output and simply don't want to be satisfied with that, the original Alpha DDoS reactor in all its glory.
ALL CRCS reactors would get a significant boost from MOX. In effect, it's giving them free efficiency without otherwise changing any of their previous engineering challenges. So if you have a stable CRCS reactor going, there really is no reason to not MOX it up once you get the materials at hand.