I'll put my two cents worth into this discussion because it's a subject I deal with every day in my job. I think you're attacking this discussion from the wrong end. Rather than discussing airframes at this point, the best approach would be to start with what you want to do. There are already different ideas in this thread about what you're looking for. I'd be getting all the players together (the MAJCOMs that use the finished product (pilots), the training commands, other Services that might want to piggy-back on the new system, the loggies that have to maintain the system, etc.) and spend some time investigating what they need in the future as a training system...train for what, train how, train how much, etc. How much has to be in the air, how much via sims, how much via classroom academics. Once you have the requirements figured out (absolutely must have, important to have, good to have, nice if I could get it but not a driver, etc.) then you can start looking at training systems (airframes and other training capabilities) to see what fits your needs best. Then it becomes a tradeoff for capabilities vs. maintainability vs. cost.. Of course, mixed up in that are political realities and other non-technical games (corporate PR, etc.). When all that gets done, you get to the selection decision. What do I need to train with in the future, not what current airframe option will do the best job in my old training scenario. Sounds simple, but it isn't