Ok, so it might make sense for each MP to represent roughly the same amount of people in Westiminster - however it does not make sense for the interests of an area (from the population's viewpoint).
Moston for example will be with Oldham - inner city area vs. a section of a different town. Drolysden similarly but with another section of Oldham including Saddleworthian Springhead. Will be better examples but why have say, rural areas with inner city areas... and why split up towns where each section is likely to vote similarly? It's not effective for the people of an area to get their voice heard - one MP's concerns are diluted by different interests within their constituency. I take it that the main interest in such a system is so that large constituency's don't have more say than smaller ones in national matters e.g. general elections but this isn't the fairer system, which would be similar voting regions (e.g. a town or similar adjacent suburbs) being best represented. This then builds up nationwide to best represent the number of working class votes vs. upper class votes in a basic example. If there are more working class in the country, they rightly should have more influence on nationwide matters - that would be fairest in my view. This doesn't just apply to "class" of course but any shared interests.
This shows the proposed English changes for any interested
http://www.bbc.co.uk/news/uk-politics-32695546