The LIbDems have paid a hard price for being in the coalition. People forget that they did a lot of good. Taking the lowest earners out of income tax was a LibDem policy for which the Tories opposed but have since claimed credit for.
Student fees were introduced by Labour, who said they would not increase them, then did. The coalition's decision to raise them again was Tory policy which the LibDems opposed, but then conceded in return for the introduction of the LibDem policy of the pupil premium which has done a lot of good.
As a Liberal Democrat I believe Nick Clegg made a mistake in conceding to support that Tory policy. The party has paid a heavy price, and sadly, this tends to be the pattern when the minority partner in a coalition government gets blamed for everything bad and never gets the credit for the good that they did.
Even so, I still believe strongly that this country needs electoral reform so that the number of MPs is directly proportional to the number of votes, as is the case in most democracies. PR tends to lead to coalitions, where a minority party puts the country before their own party interests - a concept sadly alien to both the largest parties in the UK,.