azzuri:
The RTJ should be explicit.
Even with an explicit RTJ, I expect a GM to naturally gravitate towards players whose initial concept and personal chemistry seem to be a good fit for the game. Yes, if you need players and the only person who's applying needs to be coached a little bit to get the game concept straight, then work with that person...but if you've got five slots, and fifteen RTJs, I expect--as a player--that the five best-matching concepts will wind up being chosen, regardless of what order they were received in.
Being rejected because someone's a better fit has nothing to do with how explicit the RTJ is, and equally little to do with GM experience. It's just basic human nature...we like to work with people whose vision either jives with ours, or they bring something further to the situation that we feel will enhance what we're trying to do. Personally, if I'm the square peg, I'd really prefer someone not try and force me through the round hole, no matter how well-intentioned their efforts may be.