It's now about 50 years past the time when common/shared CTAF frequencies were acceptable. There are plenty of frequencies, and congestion/confusion reins supreme on 126.7, and on many shared frequencies.
CASA should immediately start implementing unique CTAF frequencies; leave 126.7 for non-ERSA airfields; and limit shared-airfield frequencies to those fields very close together.
Yes, there will be some confusion amongst those few old pilots who haven't updated their docs or their mind in years. But we have technology - it would cost very little to temporarily install something like a beep-back radio saying "The correct frequency is...".