I think the present system with a tweak for the alternative vote (I made a mistake about the name earlier) would be preferable.
http://www.electoral-reform.org.uk/alternative-vote
When there are single issues of such fundamental importance such as Scottish independence, EU remain/leave and major changes to the constitution I think referendums are required.
Wasn't too hard was it?
You just keep on polishing the turd if you wish, it's still a turd.