Is that bad?
I don't understand the problem: If you have the memory isn't it better for SL to use it and speed up the system than to leave the RAM unused?
In Leopard applications were less responsive and I always had more than 2GB of unused memory (I have a total of 4GB). Now, using the 64-Bit kernel, I still usually have over 1GB of free memory. There are very few apps that will use 4GB of memory at the moment anyway.