Aoki you may see as a one dimensional fighter, but i see him as 2 dimensional in a 3 dimensional sport.Ground, Clinch, Striking
Aoki has tremendous judo, and through his jumping monkey master style of clinch work, he can get almost anyone in his guard, as long as he can get close to them. He doesnt necasasarily need to get a leg takedown to get the fight to the ground. And because the clinch arts(Greco-Judo-Sambo) have fewer masters and far less using them, they are harder to counter against. Less training partners, and more to learn that as a fighter may really only be helpful to you against 1-2 people in the entire division.
I rank Aoki high because he can beat alot of styles, and just becuase he's a Destructive killing machine who wears rainbow stretchy pants that would make My Little Ponies envious: it doesnt mean his style isn't dangerous.
Shields i see being really great at his one style, since his bjj bottom game and top games are ridiculous, but because he doesnt have great takedowns, alot of fighters can keep him on the feet and beat him there, making him less dangerous and thus less talented of a fighter to me.