Concur with the civilian offload....doesn't help after about the first month of Primary training.
As to the Advanced Trainer: not about ego and history, but an honest assessment of "What is the appropriate level of complexity at this stage?"
I taught in both the steam-gauge T-38A and the "more aligned with 4-gen fighters" psuedo-glass cockpit T-38C. While the C-model had some fancy toys (GPS, TCAS, VHF radio, and a HUD), it was FAR easier to teach a guy to fly---and become one with the jet---in the A-model versus the C.
Why?
Despite sims meant to prepare them to program the box, they spent significant time in the chocks (with engines running) trying to program the avionics. That would cost them time and fuel...possibly enough to make the sortie incomplete.
Worse still, the HUD made patterns/landings worse. It gave them tunnel-vision....they would only look through the HUD, completely ignoring what they should have been seeing out of the side of the canopy.
Ironically, I always found I could teach the kid to land better with the HUD de-emphasized. Once that was done, I could teach him how to use the HUD.
In short, the complexity was a hindrance, not an asset, at least until about 4 months into the 6-month course.
When I was new to the Phantom, I had a Flight Commander (F-4 Patch) that said "The best Viper guys I've fought have all been previous F-4 guys."
I asked why.
"Because they learned to do BFM the hard way." And, I believe he was right.
I think all the TX jets are very impressive. The question is, when do you need to give them heater training, Air Refueling, simulated weapons and countermeasure modes, etc? Since everything is over budget now, how much do you spend to do the right thing at the right time in their training?
Yeah, the T-38 is long in the tooth, and where it really is negative training for 4th or 5th-gen fighters is in turn radius, turn rate, energy bleed-rates, lousy vis to 6, buffet in turns, sortie endurance, range, and difficulty in landing. Did I miss anything?
Oh yeah, maintainability. And it can't fly in icing. And the air conditioner is terrible, but at least all the UPT bases are in horribly hot and humid locations.
I just think they are considering a jet more appropriate for Introduction to Fighter Fundamentals (first course AFTER earning your wings, if going to fighters) than for every swingin' g-suit hose that gets their wings for the next 50 years.