What I mean by the melody being rhythmic is that it's not just half notes, for example. It's bouncy and syncopated (kinda) and quick. Another way to put it is that it's not really the kind of thing you would sing.
Repeating sections note for note in the melody is not necessarily a bad thing. Repeating sections exactly isn't, either. Repetition can be used to great effect. It's up to you to decide whether or not to repeat and exactly how much of a copy that repeat is going to be. But anyway, you wouldn't necessarily have to change the melody. You could add in just an instrument that pops in and out, another percussive instrument, a harmony line (though that might complicate things more than you want), and about a bazillion other things. There are a lot better examples, but for some reason (it's late and I'm exhausted) this is what came to mind first:
Each section after the intro plays through the melody once, and then plays it again but changing the ending (resolving the section) and usually with different instrumentation. Really just something as simple as passing the melody off between a few instruments can be enough to make something not sound repetitive even if it is. It gives the illusion of change. This example isn't quite applicable to your piece but I think it illustrates my point well enough if you just listen and realize that even though there's several changes to different instruments, it's all ultimately playing the same melody, with differences towards the end of the phrase.
I'm probably not explaining myself very well. I'll reread this after I wake up and see if I can clarify.
I'm starting to wonder if the steady nature of the hi hat in the main section is counteracting the somewhat wobbly nature of the melody and... left hand part and detracting from the groove. Hmmm.
There's lots of different ways to do the hi-hat there. What you have works and I like it but a lot of times when you have something with a complex melody the percussion doubles it, so that may work too.