Coming in as a new director after many years of change is hard. Given that the kids have "gone through quite a few band directors" those "traditions" they have are literally the only identity and stability the program has.

You'll also find that if you go back to what was done by whomever was director before the "quite a few" that none of the things your kids are holding to as traditions were in fact traditions - it was one grade or so that did things the way they did them last year, and then it turned into "this is how it's done" from the new kids who didn't know any better.

I worked in a program that went through five directors in seven years. And there were still many parents and alumni in the town that were there before the turmoil - they told me exactly that. "None of that is what we did before with Mr. XX" or "When did that start?" were the most common remarks about "traditions" that I was expected to uphold.

Let the kids leave that want to leave. Your program will be better off in the long run without the malcontents. Teach who is in your classroom, let them whine and complain, and then build it up better for the future. Yes, your program will suffer for it in the short run - you'll be short on talented players, but those malcontents will - WILL - be doing more harm than good in the medium and long run.