As for lasting legacy; just because they were not proficient in the ring... erm, Sunny? Sunny and Sable were both with the WWF for less time than Stacy and Torrie... and what was that memorable about Sable's runs? That she was that hated in her first run that Sean Waltman defecated in her bag as a goodbye present or her 'Playboy' run with (nonHoF worthy) Wilson in her second run?
You could make a case for Sunny not being any more proficient in the ring than Stacy or Torrie was, but her legacy lied not in her time as a wrestler, but in her role as a manager. Apart from this, the company acknowledged her as the first real Diva. She was the "First" - that distinction alone set her apart from all that followed.
Sable was a former Women's Champion, the first wrestling personality to cover Playboy, and at one point one of the most over people in the company regardless of gender. How you could question what was memorable about her run and yet defend two former Nitro dancers who spent their time in the WWE doing bikini matches and shooting t-shirts into the crowd makes me wonder what the hell it was you think you were watching.