The industry is moving toward a mid-point of having the flash translation layer still implemented on the drive so that it can present a normal block device interface, but exposing enough details that the OS can have a better idea of whether garbage collection is urgently needed: http://anandtech.com/show/9720/ocz-announces-first-sata-host...

Moving the FTL entirely onto the CPU throws compatibility out the window; you can no longer access the drive from more than one operating system, and UEFI counts. You'll also need to frequently re-write the FTL to support new flash interfaces.