Personally I feel it should be harder to gain pop but much easier to lose it. I think we live in times where attention spans are much shorter. For example if my fed is 70 in pop to me I need a 70 rated show to maintain that, ie my audience tunes in next week. If I put on a 75 rate shows thats drawing a few more bods in as my show is of better quality than usual, but not going to move the dial alot. I think if i put on a 65 rated show that is below what people expect. I think that is more likely people will turn off the following week. I get the swing should probably be the same, but I think for the purposes of the game it puts the emphasis to maintain your show quality.
That said I can see why people would want it to be levelled out.