MechaPilot
Explorer
I lay down ahead of time what options I feel are appropriate or inappropriate for a particular campaign. If a player has a concept or a build outside of that, I’ll listen to their ideas and try to work with them to find something that suits their interests and the campaign, be it an alternate option, a house rule to the option in question, or something else. If we can’t find a comporomise, is that “shooting down” the character? I don’t think it is. To be shot down, something needs to have first taken flight.
I agree with your sentiment, but I would still call that "shooting down" the character. I just wouldn't be using it in a pejorative sense. If you make a good faith effort to reach a compromise with the player and no compromise can be had, then there's no shame in shooting down that character.