Personally, I think that a proven track record of a very high level of competency in the practice of law, adherence to the rule of law and the constitution, and a record and ideals free of judicial activism or legislation from the bench and a personal life that is beyond reproach, ie, high moral character, is all that any otherwise qualified nominee for Supreme Court should have to show.
If personal views of nominees were free to be scrutinized by the politicians it would wind up being a purely partisan thing, depending on which party has the majority, and just as important, it could predjudice cases that come before them, as has been pointed out.