I don't play much uber, but im sure it can handle its weight in the uber metagame. But personally I dont think there is a reason for it to be banned.
As to my thought of it now, i consider it to be a very counterable mon. When i see a team with Deo-D im not too worried as i just switch into something with taunt to cripple it. Deo is not a very good attacker on the physical/special side and really cant accomplish much while being taunted. I have seen many different variants (Cosmic power, Screen Setter, Hazard Setter, etc...).