Here is my two cents on the subject seeing that this band is my favorite band. I love this band as a whole. I will not go see this band on tour if there is no Lindsey, nor will I go now since Christine has passed away. Each of the band members added so much to the band in there own way.
Stevie has that iconic voice that when you hear it you know exactly who it is and it is powerful and kind of mesmerizing. He songwriting was also fantastic as well. Lindsey also added that songwriting and his voice, but it was his guitar playing that really was so amazing. Christine and her mellow voice tone and also her voice blended so well with both Lindsey and Stevie. She also added the piano and keyboard sound that added much depth to each song. Then there were songs like "Oh Daddy" and "Songbird" that she just carried. Mick and John were both the backbones in my opinion of Fleetwood Mac. You didn't hear much from either of them, but they held it all together musically and Mick held it together off stage I believe the best he could as there were a lot of personalities in that band.
I really think what put Stevie out there over Christine however is she was center stage. She wore these outfits that either looked like a gypsy or a witch and she flaunted it. Christine didn't seem like that short of personality. She led in a different way. Christine also had an amazing voice as well and it compared to Stevie's, but it was Stevie who was noticed more because her voice was different and amazing.
That is just my two cents.