I don't know about all of the patterns, but Billy O from Brunswick said on the DV8 Facebook page that Cheetah has been adjusted to have more oil at the end of the pattern. They maybe be keeping the names so the "casual" watcher becomes familiar.

They tweak the patterns almost every year.  Most of the animal patterns are longer than a couple of years ago.  Cheetah is still easy, but it is tougher to bank the gutter now compared to when Robert Smith use to play it a few years ago.  Shark isn't even used much with the lengthening of the Scorpion and addition of the Badger. 

Original Shark was the longest pattern, and played very well for many of us.  It got a lot tougher when they modified it about 3 years ago.  When all the patterns were lengthened more recently it disappeared.  I don't think it was any more unfair to lefties than righties.  The Scorpion at 47 feet, and the Badger were viewed as better challenges in terms of risk reward.