most people tend to wear out the outer edge of the heel whatever their gait, as that is where most people land as they are running.
Might be worth looking at Saucony or New Balance, but to be honest I agree with David - if you have found something that works for 99% of what you need, and the wear is the only problem, stick with the Asics unless you are having a real problem.
Asics are a good quality brand and the shoes you run in are designed to cope with high mileage. you are likely to struggle finding a brand that is a massive improvement, unless one of the brands introduces a very durable outsole, as Puma have done with their neutral shoes (which wouldnt be suitable for you if you are ok running in Asics support shoes).