I'm not trying to say Aldo doesn't have killer instinct. He made a career of showcasing that in strikeforce and he showed moments in his UFC run as well of violent destruction- such as the first Mendes fight. That said, he seems to me to be far more tactical in recent years- using his technical advantages over his opponents both as a striker and a grappler to take rounds and cruise to victory.
RDA lately looks more like he is looking to get you out of there- the viciousness with which he attacked Cerrone, the TKO of Benson, the way he was looking to sub Pettis even deep in the fight (I think it was the fourth round that Pettis was struggling mightily to avoid the kimura). The difference in aggression between the two fighters at this stage in their careers seems to exist.