It's not really in the spirit of this thread but I actually don't think the Westminster system would work very well with a 500+ seat Labour government.
Indeed, but you never know, it's wishful thinking but:-
500+ seat Labour Government
Push through PR
Have a practice election under PR to get people used to the idea
Call a real GE under PR
Come back with a lower majority and more of an opposition and a more representative opposition
That's the dream, huge majority, push through a huge amount of structural changes to reform how our Government works that deliver long term improvement
Less hopeful that would be the reality but would love to be wrong
Indeed, but you never know, it's wishful thinking but:-