4 turns a year wouldn't necessarily make the game 4 times longer. If it sitll takes 4 years to build a port, for example, and one year to train some knights, then you aren't going to be spending any more time managing your provinces than you did before. What you get is added flexibilitiy and strategy with unit movements, which is what I think everyone who wants 4 turns is looking for. You could even have one turn per year where you can make economic and business decisions and 4 turns where all you're allowed to do is move units.

None of this matters though, because surely the game is already completed, an they are just working out the bugs at this point.