sp and mp is a nice simple way to categogrize things and break it down into manageable chunks that can be both moderated and understood with ease.
If you try and break it down into specific replay categories then you have issues like, a replay that starts as a spar but becomes a madman, or whatever. Throwing more categories at it isn't the way to go about it.

From your most recent post I'm guessing your issue is more to do with not knowing what you're going to get from a replay before you download it?
If it's to do with being an "annoying" way of categorizing things then I don't really know what to say.
You can subscribe to the threads and make your way around the forums using the User CP. That's how I stay tuned to specific threads/boards I'm interested in without having to wade through everything?