I was about to post the same thing regarding other Conde Nast editor's part-time consults. I think both Olivier Lalanne and E Alt would be a good choice as EIC, it'd be painful to see someone new and set up a complete new team at VP (e.g. W under Stefano Tonchi). Both would make a good transition and Carine's current VP readers would stay.
I mean, let's face it, fitting into CR's shoe is like that of Hedi Slimane's at Dior Homme or Tom Ford's Gucci. Furthermore, I honestly don't wanna see Virginie Mouzat (of Le Figaro) to get the role.
Also, what's that thing about Roitfeld's or Alt's writing content standard? Com'on, Conde Nast should know and expect that, as they know perfectly well about their *stylist* background, and probably hire 'em for that, NOT their writing skill, so don't complain now. Don't forget Anna Wintour dropped out at 16 and did styling also as editor at Bazaar and New York. Plus, many know that French somehow sadly see fashion superficial and skin deep, therefore, I guess they don't buy VP for the sake of literature or deep article. As for those who like fashion and buy VP, I guess they might be as "visual-oriented" as many others.