In the old FSP days of T-41s at Hondo, it was all that was needed to send folks to the T-37. You could show up not knowing anything about flying, work very hard and do well at UPT.
Of course the more you knew about flying in general, the more time you had to study only the AF specifics such as the overhead pattern, EP standups, and the stuff they were trying to teach about high performance jet flying. So as long as they had the attitude of "I am here to become a better pilot and a military aviatior," they did well. If they had the "know-it-all" syndrome, then they suffered as many here on this and other past topics have alluded too. I too know of a guy in my Nav class at MHR who was a UPT washout with a CFI, so it does and will continue to happen.
Then T-41s went away and T-3s tried to replace them. Thanks to the troubles with that program, they too went away. For awhile we had dudes show up whose first airplane ride was their C2301 dollar ride in a Tweet. Some of them must have been reincarnated flying aces from previous wars, because I know of a few who FAIPed and got fighters as a follow on, and some who went direct to fighters.
Then the AF tried the go get 30 hours at the FBO. That was a waste of money. There was no standardization and apparently no syllabus. People who went through that program were utterly clueless and it seemed like the CFIs and the Flight Schools were more than happy to take their money and joyride for time building.
Then we advanced to the get your private at the FBOs. While the quality control was not the greatest, it gave them a base GK level of weather, airspace, some aerodynamics, some night time and some hood time. Having to take the Private Written gave them a good knowledge base, and already passing an FAA checkride seemed to boost their confidence a bit. There were still a few weak swimmers. Maybe the flight schools or examiners felt sorry for them or thought the military would take care of them. My first CFI many times said the AF would teach me something. I did not stay with that dude more than two lessons, but looking back I realize he did not know what he was talking about. People seem to have some misconceptions about what we teach and do not teach at UPT, so it is understandable.
Now that we have the T-6 and do more than we have in the past at non tower CTAF places (at least for AF UPT), this would be a good program to still have around. The new generation of T-6 students seems to take longer to catch on to what the weather means to them, the flying status, and the impacts upon their mission. The ones without prior GA (most) don't do as well cross country than their got a PPL IFT predecessors, especially on the radios and doing VFR arrivals.
I like the current IFS at Doss. It is well structured, teaches them standups and the pattern. It is standardized so there is some attrition of the weak swimmers. What I wish we could do is after we take them through that program, is to send the ones who graduate out to the FBOs to finish their PPL.
Discipline them first to our way of briefing, chair flying, aim point-air speed landings, and the emphasis on EPs, then let them go out and get some experience and more knowledge on how the aviation world works. I say this as one who started flying lessons before Nav school, got to solo, then came back 18 months later to finish my private as a rated Nav. I was a different, more disciplined, more prepared private student than before. Kinda like the analogy of going to charm school and learning all the fork ROE, then going to a barbeque where you eat with your hands and lick the sauce off your fingers. Folks who have never been to charm school have big troubles adapting to manners and such at the formal dinner, but folks who went to charm school are a little uncomfortable at first, but do just fine at the picnic, they just use more napkins and are a little neater. The military way of learning to fly is the formal dining room, with lots of rules and different forks.