[quote=B.D........................
I'm not sure a marching band could
really march to that rhythm, though

[/quote]
That was my first thought also.
I was in a marching band for 5 years and this really doesn't sound like a marching band. This sounds like a brass and woodwind orchestra and I mean that is a very complimentary way.
Nice melody and instrumentation.
As mentioned a little variety could help. Maybe add some strings to complete the orchestra. YMMV