I think Kate Jackson would have been a highly successful replacement for AM as Vicki. Betsy Durkin was awful, IMHO, and while Carolyn Groves was much better, I believe the fans had already decided if AM couldn't play Vicki, no one else should attempt to.
As for Jaclyn Smith, she was undoubtedly stunning, but if she did have a heavy Southern accent, I understand why she wouldn't have worked out as Vicki.
Speaking of CHARLIE'S ANGELS, I sometimes watch that show in reruns now and can't believe I ever liked it. The acting was awful, the plots big enough to drive a Mack truck through, and the way the actresses deliberately dressed sexily seemed more the point of the show than solving the crime of the week. Yuck!
Love, Robin