Anderson hardly ever actually tries last time he did was in the second round against Okami where he was moving and he looked like he was actually mad. Anderson doesn't try very hard until he's in danger which is almost never. He is the cockiest fighter around, if he truly tried to stop the takedowns he'd do a lot better but he doesn't give a shit. I'd say he's underrated because most fights he comes out just to screw around
Anderson Vs Sonnen just sums it all up though. Not only would he have wanted to keep it standing as he was being put in danger, but in the second fight he was going in to murder his opponent. What happened? He got taken straight down and held their. His BJJ looked improved, but in the early moments he didnt do anything to get out of the situation. He stopped a takedown or two in the second, but if you compair that to how Bisping did against Sonnen's wrestling, it just shows that Anderson's wrestling skillset isn't up to the level it is merited with.