While I see what you're saying Thorn, that doesn't change the fact that Deoxys-N wasn't given a fair test. Arguements were brought up showing his attacking stats were actually on par with some other pokemon whom we currently have in OU (since Deo-N is running a speed boosting nature and usually has to seperate his EV spread). In some cases, he was doing less damage than other sweepers, as he was generally relying on Non STAB moves to do so and in some rare cases, hidden power fire. The few people who used him and argued this point said he was dissapointing because he couldn't kill what he needed to and was always ohko'd in return. But they weren't in the majority, and DEo-N was merely banned without a test.
And I don't think Conkeldurr +1 mach punch even kills Deoxys-A. Hitmontop needed LO Technician Fake out AND mach punch to check him. Even with the higher attack, conk's probably not going to kill him.