^^This.
Every radio in the county has about 15 bajillion mutual aid/interop talkgroups programmed into it. Dispatchers need to gently remind incident commanders of these things sometimes, but then again, that assumes the dispatchers know whats in their radios and the radios of their field units.
In addition, all CPD radios already have the OSU talkgroups in them, so a patch would not be necessary; any responding CPD units could simply switch to the proper talkgroup(s), which they did anyway.
Plus, daily life still goes on in the city outside campus, and a patch would compromise the ability of CPD to respond to events in the City by unnecessarily tying up the involved City talkgroup(s) with OSU traffic and vice versa. That may have been what the City dispatcher was referring to; many agencies have policies in place to not patch their primary operations talkgroups to other talkgroups for this very reason.
There's always some confusion in the opening phase of an incident, but overall, the standard countywide law enforcement channel plan was a great success, enabling responding units (from OSU, Franklin Co SO, CPD, Grove City PD and others) to communicate seamlessly by simply switching to the proper channel on their radios.
More education and familiarization is probably necessary (it always is), but all the planning and training already accomplished definitely paid off.