You're doomed anyway you do it. You have to change the environment the parliament operates in - which means the ideological and media environment.
Not to mention that a larger "voting district" probably means you need more money for ads, flyers or election staff in an election.
And of course fewer MPs means that interest groups need to "influence" fewer people to advance their interests. Coupled with the larger " voting districts" mentioned above this seems to be a recipe for larger "interest group" influence.
Just look at the US Senate.
