Nage waza offers just too many benefits (for a mere edge): a simple solution would be if it only made throw work on other assassins/hth specs, but without otherwise improving throw/ground control (chance or damage). *Maybe* you could also keep the auto-throw on missed bashes etc., except it would only trigger a normal chance (not 100% guaranteed) for *just* ground control (i.e. no auto-throw as they already fell on their face).

Likewise ground fighter edge should probably be tweaked to only increase damage & malediction, but not the chance of it landing.

I think it speaks volumes that these edges are now the default go to-edges for assassins.