To decide on this, play with the idea and setting.

I'm always up to science. Find the two absolutes (sim and "game"), see what makes the best parts, list them then find a generic mixture of it and see what is good in that execution.

Then just play with the features. Remember though that everything the player experiences, is what makes a game to "align". Is it the graphical style? Is it the accuracy to the book? Is it the gameplay? Is it the sounds? It's all of these, and more.

I'd try to find a compromise. Make a few throws here and there and think which one is the best and pick it, evolve it, dump it, make new ones with the information of the previous ones... Finally you have something you all agree that is the AWESOME EVER.