I have learned to stop viewing the semifinal spots as something other than at-large. They will be the top 4 teams, regardless of conference affiliation, and are by that nature at-large spots IMHO.

In any given season there will be one spot guaranteed for the PAC, XII, ACC, SEC, and B1G somewhere in the system. There will also be one spot guaranteed for the highest-ranked champion of the G5 somewhere in the system, making six spots of the 12 guaranteed. Then there are conditional spots, which vary by year due to the rotation and who qualifies for the semifinals, which could be as few as one, or as many as five. But in any given season, there will be at least five spots which will be filled solely at the discretion of the selection committee.