Well I can argue
There were HUGE risks for the LibDems going into coalition with the Tories, most of which if not all have been borne out.
The trouble with being the minor partner in a coalition is that you get all the blame for the bad things and none of the credit for the good things. Lefties blame them for supping with the devil, the swivel-eyed amongst us damn them for holding back naked, right-wing Toryism.
As a Labour voter in 2010 I was cross with them for propping up the Tories, and also with the FTP act, but both were if not brilliant then understandable.
The last thing the country needed in 2010 was ANOTHER election, just like it doesn't need another one now. Two years of EU referendum campaign chaos will be bad enough.
And if the LibDems scuppered the boundary reform (and thank goodness they did, having seen some of the ridiculous new constituency plans in our area) the Tories savagely helped scupper AV. Trade-off.
The main (large) mistake was voting for tuition fees, but that is not something the political right can really complain about.
Anyway, it looks as though Sheffield Hallam's Tory voters might be about belatedly to repay Cleggie for "propping them up" these last few years if the latest poll there is to be believed :-)