That is a DM issue (if they allow it) and an issue among some power gamers that need to min/max and think they are entitled to do so without DM permisson. However, it not true of all players.
If a DM does not want it, they are in their right to tell their player, "No."
Race creation/alteration, in my opinion, should be a DM decision based on their campaign not a player's decision. The same for weapons. A player tries to pull the re-skin of race or weapons (they can talk to me about powers) in a game I run will have two options: make a new character using the races as I allow and presented in the game I am running (which mean any house rules/campaign rules) or take the door. And, I know this to be true for every DM that, I, personally, know.
The players I know also respect this (One will try CharOps stuff and, deliberately, overstep boundaries with character creation to test a "new" GM. He has no respect for a GM that does not set limits and will continue pushing the envelope with a GM that won't. However, he is non-problematic and a great player when the DM shows the can say, "No").