A great two part article.
Part 1 http://zenopusarchives.blogspot.com/2014/06/hobbits-as-rangers-of-basic.html
Part 2 http://zenopusarchives.blogspot.com/2014/08/tolkiens-wild-hobbits.html
The concept appears to be races as class is a class of its own, in a sense. If hobbits/halflings are rangers, elves are fighter/magic-users, dwarves are ... I'm not sure, perhaps barbarians (?), and humans are cleric, mages, thieves, or fighters, then what other classes from advanced books (druids, monks, assassins, etc) could be made into classes?