Omar was supposed to be an antagonist, so of course he's going to struggle with Omar. There's a story arc around him and his boyfriend getting killed. That's how Avon dealt with issues. You're acting like "one stick up man" isn't a pivotal character in the story. Case in point, there was protocol to deal with them which is why as soon as Wallace saw Omar's boy in the arcade, he KNEW exactly what to do. That shows that the shyt wasn't new, they knew how to deal with dudes like that. Slim Charles, with Avon at the helm, took out a couple of other issues.
Slim Charles under Prop Joe did what? It's been a couple of months since I've gone through the series but all I remember him doing when Marlo was popping was drive around telling people to relax.
That and killing Cheese at the very end.
So as far as the original point goes, nah I don't think Stringer > Avon. Stringer failed at almost every thing he did and Avon enjoyed his time on the throne.