With a POD on or after 2010, your challenge is to make David Miliband the leader of the Liberal Democrats. Bonus points if you can engineer a David vs. Ed vs David showdown.
The Lib Dems are not Blairites.
Both were centrist, but that is more a position on the political spectrum than a specific ideology. The Lib Dems generally see Blair and his associates as too statist on civil liberties, in particular. They are also less hawkish (being more open to nuclear disarmament) far more interested in political reform, and in some respects, more economically interventionist. They advocated Labour regulate the banks better, and I get the sense that even Clegg was more in favour of progressive taxation than Blair, as he kept the Tories from scrapping the 50p tax rate for the first few years in the coalition, and succeeded in negotiating it up to 45p rather than 40p, that Blair had and Osborne suggest reinstating. Miliband would not be particularly left wing for a Lib Dem, but he would be a bit out of place in the party given how he doesn't agree with them on some of their defining principles.Wut? Under Clegg they pretty much were more or less that, they certainly had a superior claim in some ways to that mantle than Cameron. Though equally, DM would be pretty acceptable to the Lib Dem left, policy-wise he's perfectly compatible with them, that's not really the issue here.