[ThePillsburyDoughBoy]

The problem with defining an uber as centralizing the metagame is that forces that are centralizing aren't necessarily overpowered. As an example let's look at Scizor. In the last batch of usage statistics, Scizor was found on an astonishing +30% teams. Surely a pokemon that is being used to such an extent must be overpowered? Well, not really. Scizor's centralizing presence isn't due to its ability to win games singlehandedly, but rather that it can deal with a large amount very powerful threats , ie Terrakion and Dragons, and also give you switch advantage. Since Scizor is used so much I have to dictate my style of play to it. But is it overpowering? No. This thread of thought doesn't apply just apply to Scizor, but pretty much all popular "top ten" pokemon.

IMHO, if really wanted to summarize the definition of an uber Pokemon is, it would follow this idea: "A Pokemon is uber when it can consistently perform an intended goal that is exceedingly difficult to prevent or stop and there is an extremely limited amount of viable options to prevent or stop said Pokemon."

In the context of Excadrill it possessed both of these properties. When it set up a Swords Dance, it could easily sweep teams due to having a massive attack stat and jaw-dropping speed. It could consistently perform its goal of sweeping teams. Meanwhile, it had a very small pool of Pokemon that could check or counter it. Gliscor, Brongzong, and Skarmory were three defensive options for dealing with Excadrill; while CB Mach Punch Connkledurr, Iron Fist Mach Punch Infernape, Azumarill, and ahem opposing Excadrill were the offensive options of dealing with it. Deoxys-S was in a similar vein, consistent performance of screens/hazards and a very small pool of pokes could stop it from performing its goal.

While centralization is apart of being an Uber poke, its not what makes them uber, it's their characteristic of consistently performing a goal with a very small amount of viable Pokemon to stop it.