I think they should be paid a lot more to avoid Westminster becoming the exclusive preserve of those with family money and/or a very high-earning partner to support them. MPs do work phenomenally long hours, have a lot of responsibilities and, those with constituencies beyond a commutable distance from London, don't get to see much of their families. OK, they earn more than many but, since a lot of them come from the law, business, media, senior trade union positions, occasionally medicine, they could expect to earn a lot more elsewhere.
I completely understand that the public aren't keen on the political system but the few backbench, constituency MPs I have come across have worked really hard and cared very much. Imo, the greasy career-politicians that we all despise are partly the result of not paying "ordinary" MPs more and allowing policy wonks and those who feel that they are entitled to rule to run the place.