Without TRIM, there's no way for an SSD to know (without cheating) which blocks are considered free by the filesystem. Increasing the FTL free space allows an SSD to absorb more writes at full speed before needing to GC.
A SSD that understands NTFS and the other major file systems while "cheating" is not impossible. Also The TRIM command does not work on RAID volumes so there is plenty of room for improvement.
