George Will is an under-appreciated columnist, I think--he's not an attack dog or a dazzling stylist, so he doesn't have a passionate following, and he's been so good for so long that it's easy to forget how effectively he practices the art.
Others will have to weigh in on this, but I've always believed--and thought that others believed--that Will is one of America's best writers and thinkers and THE great columnist of his generation. No one else even comes close. In fact, you might argue that Will is the last of the dinosaurs: I'm not certain that any newspaper columnist will ever again attain the level of influence and achievement which Will has.
In addition, I would guess that some very large percentage of political writers between the ages of 25 and 45 chose their profession at least in part because of Will. (This goes double for pretentious jerks who insist on using a middle initial in their byline.)
As to the matter of Will's skill as a stylist, I'd argue that Will isn't just a great and smart political writer. In truth, he can do just about anything. From the astonishingly light touch he uses on pieces about his son to the iron grip of heroic certainty he brings to his baseball writings, Will could have become famous as just about any kind of writer--sports, features, essays, non-fiction books. He hits to all fields with power.