From memory, I think the Ginola sale was more down to Dalglish - probably saw him more as a 'luxury' player when he was trying to tighten us up with a 'defensive' style of play, and probably couldn't handle him, unlike Keegan.
For the same thing, basically think of how Laurent Robert was handled by Robson and Sounes respectively.
In my opinion, Ginola was great when he first arrived - noone knew how to deal with him. However, he got kicked up-a-heigth at Arsenal one night, got sent off for reacting, and never seemed the same player for us again. He was also linked with Barcelona which seemed to turn his head.
It wierd how the club never seems to handle 'Gallic' players very well - you wonder how long Cantona would have lasted, has he found his way up the A1??!!!!
did alright for Leeds