I think the referendum is on the wrong question. What they have asked is:
Would you like:
A) a new system of voting where the party with the most votes doesn't necessarily win
or
B) to keep the current system of voting where the party with the most votes doesn't necessarily win.
Out of the two options, maintaining the status quo makes more sense to me as it reduces the chances of a hung parliament.
Proportional Representation would be a far more interesting option, albeit likely to cause a hung parliament every time. I feel that any non-PR system makes a mockery of the whole system of suffrage. Let us not forget the shambles of 2005:
Labour won 35% of the vote but 55% of the seats
Conservatives won 32% of the vote but 31% of the seats
Lib Dems won 22% of the vote but 8% of the seats.