The page split / fragmentation concern is often overblown. Remember, one INSERT, but you may read the row 1000, 10K, 100K+(?) or more times. Particularly given the availability of partitions, reorganizations, online rebuilds, etc., some fragmentation can be dealt with far better than using the wrong clus key just to reduce frag on the single INSERT of each row while drastically harming the performance of the vast majority of future SELECTs.