4th edition design covers one area of generating monster and I find that it's not enough. If I want fast monsters on the fly then yes it's good but it doesn't provide enough in-depth building for my tastes.
The joy about "organic design" is the fact that it can be anything from simple to complex depending on the way you want to build your monsters. "Plug and Play" monster building is fine but I find it can be very limiting when I want to more depth.
What about 4E monster design meant that you couldn't take your time and lovingly craft a detailed monster? Just because you can deliver a playable opponent for your PCs in five minutes doesn't mean you have to stop there. If it doesn't deliver what you want from it yet, continue to modify and tweak it. If it does deliver what you want, where's the problem?
A system with the option to quickly design a monster doesn't stop you from taking your time. A system where you have to take your time to make a monster means that you can't just make one quickly.
Guess which one I prefer.