Remember that if you have anything else, you'll just end up with coalitions galore with no way out of it. Almost every country that has gone to anything else has had that and none have been in a position to get out of it (NZ came close a few years ago but blew it). Indeed certainly don't go down the whole country as 1 constituency route as they tried that in the Weimar Republic and look what happened.
The theory is that people are not voting for the government, they are voting for who they want to represent them in parliament. But the media and the way the ballots are printed help keep the status quo. If ballots didn't have the party logo on it, then people would actually have to know who they are voting for and could help crack the system.