From what I can personally draw from Ecchs, he's pure genius and is potentially the most dangerous person introduced in the story. Except for the fact, that as Friv notes in Ecchs profile; He enjoys the game more than the conquest. I get the distinct feeling that Ecchs views the world as something alike a complex game of chess: though he'd like to eventually win, he'll take a loss as long as he had fun along the way. Oh and he also has an instinctive urge do things exactly the WRONG way, just becuase its more fun that way. (like making three lefts instead of a right)
As for his potential, He's managed to create a weapon that can create a specific dimensional distortion (so far as to undo the past). That in itself more or less implies that he could control reality as he see fit, well, assuming he ever got the details down (something about not creating megalomaniacs).
He's also managed to make a laser-guarded fortress at the docks for less money than the contract to destroy the building (i mean we're talking handyman lasers-from-duct-tape level genius here). Though some of the earlier material I am suspicious of its complete cannonity with universe, Ecchs is a(n) [evil] businessman and if we note the appearance of the fortress in this last bit, If Ecchs actually stuck to run-of-the-mill villian procedures like lasers and atlantean anti-psi suits (remember senior thesis! …i think) instead of spending his efforts on absurd things like ninja-robot-zombie trees, he'd be playing the part of the oligarchs right now. In fact i wouldn't be surprised that the only reason Ecchs did something as hackneyed as make a flying death fortress was becuase he could HIDE IT IN PLAIN SIGHT (I mean who wouldn't do that, I know I would).
Really, I've really viewed him as more as an anti-hero than a villain. I mean, what kind of villain builds a multi-billion dollar business with the intention of squandering all profits on a war that he has no intention of winning? Oh yeah and half his company is friends with Lucky Ladd. And his 2nd-in-command is his arch-enemy's sister, and they (occasionally) have family dinners still.
Friv's maintainence of Ecchs as the quirky professor even into this critical time (as opposed to just druing lighthearted hijinks time) leads me to beleive that Ecchs is really really powerful, he just can't be bothered to do things in such boring ways.
</rant>