Ask any real game developer there is, they all say that when they envision the game they have all these kinds of ideas and how its all going to be super amazing.
Then they go ask the coders for what can actually be done and they need to cut alot.
Then as time goes by and they realize that they went over their head with the whole thing they cut more.
Then they cut more to save more time.
Then they cut even more because its too advanced, noone will play it.
Then they cut even more.
Get the picture? Cut more, get down to the basics of what you want, and get down to something you can do with your current staff in a set timeframe. Dont go thinking you have all the time in the world, because you dont.