I took the argument more of, the T-X is going to be very easy to fly and we'll cut over half the T-38 syllabus when it transitions to the T-X because you don't have to worry about stubby wings, underpowered compressor stalling engines, and a shitty turn radius.
Therefore, it makes more sense to give the T-X to Fighter Training Squadrons to have wingman learn how to employ it as a weapon right after an IQ check.