I think it interesting that one of the prettiest musical moments this year that received some of the greatest crowd response in the shows that I saw suppports your arguement here. The Bluecoats play the Boxer (Paul Simon) chorale style about 3/4's of the way through their show...it is a brief but powerful moment, well played and beautifully arranged. The music very much stands on its own.
I am admittedly old school but I have enjoyed many of the changes creatively and technically that have come about in DCI. But like the OP I fear that drum corps identity is getting lost. If we do end up with 10 "super" corps' it will be the same as any other sports league with all of the tripe that comes along with it. Once that happens, and the activity moves the furthest away from its roots as a youth activity, we will have lost forever all the things that drum corps has meant to so many.