Yes you keep saying so. But why? I don't see any reason why they should risk a tried and tested formula which has resulted in the biggest subscription game in the world just to combat a little bit of subscriber trickle off after nearly 9 years on the market.
Maybe once subs drop to 6 or 7 mill it might be time for a radical change (which would likely be a last grasp or death rattle anyway) but as it is this old game is trucking along better than anyone could expect it would in its lifecycle, and better than any game which has never adjusted their subscription pricing has any right to be.