You can see no requirement in a rapidly changing battle like Lybia/Mali for a wide area battlefield surveillance radar? Really?
I know it's very difficult to discuss capabilities on a public forum but I'd love to know what space-based sensor available to the French military can find a small group of technicals in a vast area, track that group and then cue on fast air - all in real time? I wouldn't mind knowing which space-based systems are 24/7 too - surely the French Helios EO birds are sun-synchronous?
GMTI is a much sought after capability nowadays and Sentinel, JSTARS and later the SKASaC were heavily used in Libya. The U2 boys might also be a little hurt that you think they haven't been involved recently.
It's certainly no odd publicity myth that Sentinel did well in Libya - tracking enemy vehicles over large areas was what it was designed for in the Cold War so it's no surprise it performed well.
It's all academic as it's a capability that will almost certainly get the chop in the next few years, but to say we didn't need it seems very short sighted. Only the big boys get to play wide-area persistent GMTI and we've got it for comparatively peanuts (the bid from Boeing to provide JSTARS instead was ten times the price).