That they experienced very potent bashing from dex stsf builds with stsf charged.
Can you look and double check it?
stsf is evil enough with damage/defense/noflee, everybody and their mother is stsf, and elf bashing will not make it less popular.
As an aside note, I don't believe this legacy can be balanced in its current shape. It will be either overpowered or useless. Probably it's easier to completely revamp or remove it.