If I had my "druthers" DCS would have:
A PT-17 and a training campaign to mimic the WWII training syllabus
An AT-6 and a training campaign to mimic the WWII training syllabus
A P-51, Spitfire and/or P-47 training campaign to mimic recent syllabi
A T-34 or Texan II/Toucan and training campaign to mimic recent syllabi
I'll settle for a T-38 training campaign for the F5 (close enough to a T-38 for me) or a REAL L-39 full-syllabus that basically takes you from the T-34 to a "tactical jet"
While I don't need a TH-67 or UH-72 and campaign, I bet quite a few people would benefit greatly from a training campaign that mirrored the Army's UH-1 training from zero-hero.
I'd really like to see full training campaigns for all of the aircraft available. I fly for a living, and am a former UH-60 pilot. I'd love the AH-64 or OH-58, as well as many of the fixed-wing stuff, but I have never had training on dogfighting, weapons-systems, tactical fixed-wing operations, etc. Full campaigns that take you from "what's an airplane/helicopter?" to "advanced operations" as a real training regime would be much more enjoyable and productive than me blindly trying to figure out how to do anything in one of the aircraft.
I would honestly use DCS much more if I could progress through those campaigns. I haven't recently purchased anything or even used the sim because I can never really get to a level of proficiency to enjoy it. I know there are F-16, A-10, etc., guys on here that just "do what they do" with great proficiency, but that is really a small percentage of potential customers. Then there are the guys that have no real-world experience but spend hundreds of hours figuring this stuff out on their own with little guidance (which is an amazing achievement) but that requires a commitment well beyond what the average person can do.
I'm not saying make it a game and easy. I WANT the realism and complexity, but I want the training to get the proficiency as well.
I think doing the "baby steps" into tactical flying would get a lot more people interested and keep them coming back for more, which is good for all of us.