I find it hard to hate on cosmetic DLC because it is just that: cosmetic. No one is making you buy it, nor does it affect the game in any real meaningful way. Its just there to make you look different, and if you are willing to spend money on that then more power to you. When it comes to multiplayer games, I actually prefer cosmetic DLC to any kind of "Pay to Win" approach.
The COD4 map pack was pretty bad. 4 maps for 800 points. Of the 4, 2 of them sucked, and 1 of the two good ones wasn't even in most of the game rotations.
Also, See the Future for Fable 2 was pretty underwhelming. Basically just a playable ad for Fable 3.