Any decently experienced Champion would know that Asura is one of many ways to take out your opponent. Tactic along with a creative mind is useful when using them for PvP/MvP, and they are extremely effective for both when used correctly. Many make the mistake of just using them as an Asura machine, but that really takes all the fun out of the class. Sure, it gets the job done in most cases (With a proper build their reduction shouldn't matter unless they're a frenzied LK with an Ahura Mazdah on). Throw Spirit Sphere and Occult Impaction are two very powerful skills that can deal a lot of damage very quickly. Pairing that with quick reaction time and moving about with Snap(Body Relocation on most servers), a Champion can be a very formidable class without using Asura.
Assuming your talking about high rates. I have never seen a good non-asura champ in my high rate experience and I'm pretty convinced that it can't be done. Champs are simply too disadvantaged in high rates. They can't whip out enough damage-per-second in comparison to almost any class. Sure you could TSS someone with insta-cast and snap away, but that does maybe 13k-20k ish? On a server where most players have >100k hp, its really just not enough and its highly predictable and pretty easy to counter.
Occult Impact a powerful skill? Maybe so, but again not good enough damage-per-second. It's certainly not spammable and, worst of all, you have to get close to your opponent. While you might whip out a good Occult Impact, any idiot could stun lock you with wtf-aspd before you can do jack. Plus, champs are rather squishy. They cant take that many hits.
s*** is rigged against champs. Snap may be your best friend for a while, but you can only snap so many times before your labeled a flee-ing nublet. It just doesnt pan out.