Flo had an entirely different style of singing than Jean. Flo's voice is much thicker and heavier. I think she would have done better with a much heavier r&b sound. more in line with what Glady's was doing. the Frank Wilson material for the 70 Sups was ethereal and light, even though the productions were big.

I think Clay MacMurray and his "soap opera soul" would have been a better match

As for the future of the group, I don't know what all would have happened. Flo had a lot of emotional demons and so it's possible she would have still crumbled. I don't know that Flo remaining in the group would have changed much of the course for the DRATS. Cindy really didn't do a whole lot other than fill the 3rd slot - certainly no fault of hers though. Berry was looking for a period of time to groom Diana, expand her horizons and more firmly establish her as a mega star. Flo's departure really didn't have that major of an impact on their records - she already wasn't on You Can't Hurry Love and rumor has it she wasn't on Reflections either. HDH's departure and the changing musical scene is what really lead to the DRATS chart irregularity.