True.
It just seems like they should already have the game done since all the game series now adays come out every year/2years
Yeah, but like my edited post says, the more time for development is always better. Thats why Valve and Blizzard excel in the industry. There's always better quality with more time to develop. Also, keep in mind--BUG squashing.
Besides, this dev team has had a few years to develop thus far, and have a larger team, as FalloutFTW said. So it will be worth it.