To my mind, it's more fundamental than technical refinements.
Parrots are fun because they are so intelligent. It comes across in the way they look at you and clown around. So I always think the best parrot shots are the ones where they're obviously sizing you up ... or just teasing you.
More generally, bird photography has progressed by leaps and bounds over the past 5-10 years, now that digital has made it less of an effort to carry both a scope and a camera. That's not to say bird portraits are out, but what's wows the birding community these days is an action shot which shows the bird's behaviour in a new light.