MLB has been very sloppy.Agreed completely.

Requiring batters to run the bases is rules-lawyering gone mad.

Agreed again. In fact, I recall seeing a game that was very critical -- I don't remember if it was to clinch the division or to win a playoff -- and the batter hit a "walk-off" home run with the bases loaded and the team needing one run to win. He got as far as first base when he was overwhelmed by the mob of teammates celebrating the win. Because he didn't complete the trip around the bases, he didn't get credit for the home run -- only a single -- and got only one RBI instead of four. Stupid.

Update, 15:00: Aha, found the story of the "grand slam single" in the Wiikipedia entry on walk-off home runs.