It has always been the case mate, we were all on different contracts when I was there from 98. Its just one of things you have to put up with in the Middle East, and lets face it in the world of contracts! After 6 years of constructive lobbying our contract was to be increased to that of the other controllers, however, for other reasons completely separate to this issue I had decided to move onto UAE.
I don't know where you got your figures on the cost of living price rise as Oman is still 1/3 the price in rent compared to here in UAE. The unit I am in now is very similar to the standard of appartment I was in Oman. I was paying 300 OMR (3000 AED) per month in Muscat in a central and well sought after town location and I pay 1000 OMR (10,000 AED) here and I am not even near town.
As with any contracts there are always good and bad points and it really is up to the individual to see what suits. Do your homework and get the facts for yourself, don't listen to rumor and innuendo.
Muscat is a sensational place to live for both the countryside and the people, and far more affordable than here in the UAE. Even based on the current contracts on offer, the Oman deal still comes out on top.