I have two trainer modules, and will buy the third one at some point. I also have that helicopter that no one's ever heard about :P. And I do fly them all and enjoy them.
For me, DCS is not just about combat, it's about learning and using different systems and different procedures, and above all - flying. I do like to blow things up, but combat capabilities of an aircraft is the least important factor when I'm choosing whether I'll buy it or not.
Let the devs decide what modules they'll make, and hope that even the most obscure ones will find their customers among true aviation fans.