Link? I haven't once seen it discussed here on these forums in any topic. Nor have we ever had a trial period in testing lower round counts. In fact, since raid has started the round count has never changed. It's always been 10 activator rounds and 1 practice round. Even in the weird 1 year anniversary edit the round count remained the same.
Except it's hardly a balance. There's maybe 5-10 small fast maps, where as the rest of the maps are from medium length to un-fucking-believably long.
The best way to determine balance is to test. Lowering the round count may yield some surprisingly good results. Or, as you assume, we may be better off with the rounds as it is.
Point is, you have to try something before you can claim it is bad. And since overplayed maps is a recurring problem since 2012 and beyond, thinking outside the box and trying new things might help find a better solution. This is how we originally came up with raid and it's features to begin with.
As I said in my original post, removing maps will not solve the overplayed maps problem. It just creates different "overplayed" maps. And that's not a problem you should be happy with or accept.