Smogon describes Deoxys-N as "Horrible in every way", "useless", and "100% outclassed". It also has the distinction of being the least used Pokémon in Ubers, even less than Shedinja and several other Pokémon that aren't even in the tier. So if it's so shitty why is it still banned?

I say put it in OU and see how it fares.