I don't think they'll be wiped out. They'll lose most of the people who voted for them in 2010 but I think they'll gain support from disaffected Tory 'wets' who want a protest vote but, for reasons of dogma/tradition, would never contemplate voting Labour.
To be honest, I'm not sure there are that many one-nation Heathite types left in the modern-day Tory party's support base - there are a few touchy-feely Tories, granted, but on economic policies there's little to separate them from the Tory hard right. I can't really see how the Lib Dems' current strategy is going to win them any friends, really. Disaffected left-leaning voters won't touch them with a bargepole in 2015 and the more liberal-minded Tories will most likely stick with Cameron - leaving the Lib Dems with tactical voters and a few remaining right-wingers who don't have the bottle to vote Tory. The way I see it, Clegg will step aside after the next election and open the door for someone like Tim Farron to take the reins of whatever's left of the Lib Dems. A poisoned chalice if ever there was one.
I've also noticed that the Lib Dems have been stepping up their attempts to rehabilitate fraudster David Laws over the last couple of weeks, no doubt with a frontbench role in mind following a future reshuffle. This must be that 'new politics' Cleggie promised us.http://www.thisissomerset.co.uk/Bid-cut ... story.html
The Lib Dems: circling the political plughole since May 2010.