Hi, according to this http://forum.mikrotik.com/t/ftp-configuration/75915/1 please consider it as a future request, others have it why not routeros too?
My opinion:
I hope the staff use the time for fixing the bug, first.
For ftp server, I can imagine only one Linux machine, with raid, hard disks.., instead of one OS for Router…
Thinking about RouterOS: we can do near anything… I do not know one system complete as this. The bugs? One price for try to have the best.