I'm A Banana
Potassium-Rich
I've actually never encountered a gamer that argued he should be allowed to use anything and everything from any setting he liked in a game, or called me uncreative for disallowing things like the warforged outside of their setting, except on the internet.
I'd think those gamers would be as rare as the DMs who don't listen when the player has an idea they'd like to bring to the table.
And, again, the "uncreative" thing isn't about you, it's about a given setting. And settings have other needs than to allow every sort of creativity to tromp atop it. Birthright isn't as creative, character-selection wise, as Planescape. Big deal, they're both fun in their own way.