Del Rio is actually a good coach, which would make it a surprising hire for the Raiders. He has a solid defensive philosophy that is focused on stopping the run - 10 of the 17 defenses he has coached have finished the season ranked in the Top 6 in total defense.
Like Carroll, he grew up in the Bay Area and is known to be well liked by his players. He had a couple successful seasons in Jacksonville, going 12-4 and 11-5 with a playoff win. But he could not overcome the incompetent management of that franchise. His philosophy is simple - run the ball, stop the run, play through the whistle. It would be a mature hire by the Raiders, whom you can expect to play more physically on both sides of the ball if they make this hire.