First of all, Whitner was in a dead stand still, while Higgins was already sprinting past him, and you expect Whitner to turn around and get to top speed in less than a second to tackle the guy that was already sprinting as fast as he can in the same direction? That makes no sense. Whitner could run a 4.0 in the 40 and you're not going to catch up to a guy while you're flatfooted and he's already running.
Second, you make it sound as if its easy finding a safety who is great at both defending the run and the pass. There MAY be three in the league... tops. Whitner is not a cover corner or a ball-hawking free safety. He is on the field because he can come up into the box, make tackles, cause havoc, and be a team leader. He is decent in coverage. If you honestly thought Whitner was going to come into the league, break on routes and intercept passes, and catch kick return-receivers from behind, you really should just find another sport to watch.