The Dodge Animations and Behavior Entries already existed in the base game release meaning that Bethesda was at least thinking of adding this feature in, they most likely just ran low on time and back burned it in favor of DLC's.
The ONLY reason Dodging did not work by default is because a slight edit to the behavior files that disabled them and if you know what your doing it takes all of a couple minutes to correct, in a way that does not force the use of Script Dragon and will work faster processing wise then using this released version.