All of a sudden, going back to fly from Essendon's Class C seems an attractive option again, despite the higher landing fees.
And if 6 aircraft in the circuit is considered too many at a Class D aerodrome, what about those non-towered CTAF aerodromes? Pt Cook sometimes has as many as 6 or more aircraft doing circuits plus the odd aircraft or two doing practice NDB approaches. And it will probably attract even more when YMMB becomes a Class D.