I really would have liked to see a system that has some variance based on the number of candidates (for example, if there are fewer than 6 candidates, a 3-member chamber; 6 candidates or more, a 5-member chamber) along the lines of what we managed to do in Lincoln.
It is true that expansion/contraction of region population is unlikely to impact overall candidate availability in all but the most extreme circumstances, which is why I believe pegging size (within sustainable parameters for the game as a whole) to level of interest should be the metric, thereby ensuring elections are as competitive as possible regardless of candidate interest being high or low.
Now, if I was doing this federally, I'd be using a different metric, but alas...
Section 3. Every Parliament shall continue for three months from the first meeting of the House, and no longer, but may be sooner dissolved by the First Minister, pursuant to certain provisions as established in this Constitution. The number of members to be chosen shall be no fewer than four, not counting the First Minister. If seven or eight candidates declare, five will be elected. If nine or more candidates declare, six shall be elected. If, however, fewer than four candidates declare for House of Commons before a snap or general election, the election shall be postponed until at least four candidates have declared.This is the current seat allocation formula from a recent amendment. I'd personally say that the new system we very recently enacted is more than sufficient, and that this attempted reform is short-sighted and counter productive.