Move the 70-300 and both 18-135, add in your gift cerftificate and get the best 70-200 you can. a non-Is 2.8 if you can manage it, IS if you can afforde it. Id always choose the bigger apperture over the IS when talking sports as your shutter speed will somewhat negate the benefit of IS. The 7d is a fine little body. Older 1D are very nice but, I think one always chooses glass over body and imho , your long glass is your weak spot.
I've seen your work and fundamentally its solid. Where there is room for improvement is isolating your subject from the clutter. You are going to achieve this three ways. The first and most important is thinking about where you stand and setting it up so the background is clean and hopefully distant. Sometimes kneeling can change everything. The Second is to crop tighter and tighter, then tighter some more. The last is that longer and bigger aperture glass. You can isolate with Bokeh shooting wide open and more length makes tighter crops possible. Equipment is important but, no panacea and you always need to use what you got, right?
Throw your long glass on the 7d and that 24 on the rebel for the jube(celebrations). Leave them there and focus on where ypu are and whats behind what you are shooting.
