Corruption,
You have omitted three points that must be considered before your own list.
Look at your life to determine whether you have the time necessary to create and operate the game you intend. Do you have it? If not, don't start. Factors include, but are not limited to: (1) your work schedule; (2) your spouse or significant other(s); (3) your family; and (4) whether you intend to carve large chunks of your time to devote to other hobbies, like macrime.
Look at the people you want to bring on-board as staff. Presuming you like, respect, and can work with them, examine their life to determine whether they have the time and motivation necessary to participate and assist you. Do they? If not, don't start.
Look at the people you want to bring on-board as players. Presuming you like, respect, and want to entertain them, examine their life to determine whether they have the time and motivation necessary to devote their time to your game to make it better. Do they? If not, don't start.
Ignoring these three points will likely result in your losing any motivation for running a game.