I wonder if it's possible to wrong warp out of the great plateau (ex. Entering a shrine, exiting during the Ganon cutscene) This would change speed runs forever

You cannot get past the barrier of the great plateau. The game will not remove this barrier until you have the paraglider. Even if you could with a wrong warp, you'd void out. Besides, any wrong warp glitches would have to exist in another save file and transfer to the new one which would make the run invalid.