I managed to avoid that question the last time it was asked. Unfortunately, I don't seem to be as lucky this time.
Some countries have changed their voting system without holding a referendum. France did it twice. To my mind, this has less to do with what I think and much more to do with what the public expects.
If a compensatory model were proposed with the underlying principle that voters in a given region would have their own member, personally, I would find that acceptable. If the public decided a referendum was needed for such a change to have public legitimacy, I would support that as well. I wouldn't say, from the outset, that a referendum was, by definition, necessary. If a logical proposal based on the principle of individual representation were put forward, I think it would be legitimate to go ahead without a referendum.