The revival of Whose Line has been a success in America and they have brought it back on the stage with the original cast in the UK and they could do it with a mix of regulars and up and coming comedians like they do on Mock the Week. They are struggling at present for something for Alan Carr so why not bring back the show that made him famous with other up and coming comedians and some big name guest hosts.
Everyone says they should bring back Whose Line Is It Anyway, but they already did, except they called it Fast and Loose -
http://www.ukgameshows.com/ukgs/Fast_and_Loose
Rather oddly in all the publicity for it they made great play over the fact it was "from the producers of Mock the Week" and didn't make a single reference to the fact it was also from the producers of Whose Line, despite the fact it was the exact same format, maybe there was some kind of legal issue over the name. But it was absolutely identical. It was also bloody awful, about as spontaneous as Big Ben.
As for Host The Week, the whole point of putting it on a Thursday, as mentioned in Broadcast last week, was as part of a drive to run entertainment throughout the week and not stick every new format on a Friday. Clearly it didn't work here, but you know.