Nothing is wrong with coalitions but they are demonised in the UK as weak and unstable. FPTP is an ancient system from before the time of parties and needs to be reformed.

There can be a sense with coalition government that people are removed from the decisions made behind closed doors - politicians trading off with each other.

I don't accept that myself, but it's ecactly what happens to the Liberal Democrats in 2010 - they entered a coalition, agreed to policies that their voter base didn't accept and paid heavily for the sense of betrayal it fostered.