I've seen quite a lot of people trying to make a game or planning to do one. Most of them start with the story they want to tell by the game.
"It will be the game of you becoming an ultimate bad-ass and killing dragons and yelling at stuff."
Unfortunately, they are usually talking about the story in the book kind of sense - more like a lore. Something about that kingdoms in trouble and this hero doing this and that, meeting this people... that is a great start if you want to write a book. If you have this kind of idea, the story you want to be told and it's deep meaning - stick to the making of a book. Books are still cool. You know - like a Game of Thrones. It is a different kind of medium and your story will be appreciated much more. Seriously, remember how almost all the game adaptations of movies are horrific? Yes, different kind of media can learn something from each other, but they engage people in a different way and we should take it into the consideration.
"Stay a while and listen! ...they never listen."
The great example of game that is trying to tell the story by literally telling the story is a Recettear: An Item Shop's Tale - watching streamer (itshafu) play through the first few minutes with a resigned sigh "there is waay too much text in this game" was everything I needed to see. Clicking through tons of dialog bubbles with little interaction was obviously boring and of course - she didn't read it. While extensive dialogs and other than main character actions are great in a book, it rarely work in games. After all, the games are about taking part in the story and living it - more than watching it happen.
So, you really want to make a game? Great, start with the experience you want to create. Not the lore, not specific mechanics, but what you want player to feel. Is he supposed to be the commander fighting for his country? The heroic saviour of the world? A survivor trying to get by? Or maybe you want the player to feel like a little kid exploring a whole new world? That is the core of the game. The story you want to tell. Mechanics are your first tools to deliver the narrative of the game. Choose a style of the game that will suit the best your core experience. Don't be limited by some idea of a genre, it doesn't really cut it, and game designers have (or should have) a discussion about what it really means anyway (check out "extra credits" great guyz).
If you think you will make the experience of a war leader better in a close third person view rather than detached tactical view, go for it. Guys who made Mount & Blade did that and it works. Don't be afraid to explore the particular nuances of experience you wish to create.
If you, without a doubt, picked RPG as a way you want to go, maybe you should think again - is it a story or the experience I want to tell? Than go and write a book. If it is your first game, never go for an rpg. They don't get finished.
