The problem with Pillars' distinctions "within" builds is that those distinctions don't really interact much with the abilities and limitations of the class itself. Sure, instead of a bow rogue, you could build a sword and shield melee rogue or a scroll rogue- but that can be done with nearly any class in pretty much the exact same way.
If you disagree, then perhaps you could explain the crucial differences between Pillars' classes for us.
Um. Okay. I'll give a couple of examples.
Rangers have animal companions. You can build them any number of ways around that. To take just a few simplistic examples: you can pick talents which boost pet damage, and choose weapons and other talents which synergise with that, making the pet the main damage dealer (example: Merciless Companion which gives a massive boost if the target is suffering from a DoT effect, plus Remembrance or Tidefall or Bleeding Wounds). Or, you can pick talents and abilities which boost pet defences, while picking talents, items, and abilities, which boost /your/ damage. This makes the pet a meat shield which pins them down while you waste them. You can do either of these as a melee build or as a ranged build. That alone gives you four different ways to build your ranger (ranged/hurty pet, ranged/tanky pet, melee/hurty pet, melee/tanky pet). All of these will require different tactics, and will have advantages and disadvantages depending on who you're facing, and of course play completely differently from any other weapons-oriented classes, because they revolve around the various ways you and the pet coordinate. (And here I'm not even getting into firearms-specirfic ranger builds, with Gunner, Powder Burns and what have you).
Barbarians have Carnage. They kind of stink at single-target damage. You wouldn't want to go one-on-one with a dragon with one, but in a dragon fight, you would want to send the barbarian to wipe out its minions. Now, barbarians synergise especially well with weapons that confer status effects on-hit or on-crit, because that also applies to Carnage. So, for example, you can build a CC barbarian: give him a weapon which inflicts a status effect -- or one in each hand -- and send them into the fray. One example: the Spelltongue rapier which steals status effect durations. A barbarian with a Spelltongue fighting a mob -- or even a single target -- will be able to keep up positive status effects forever (Savage Defiance, for example, which continuously regenerates stamina, and naturally anything you can confer with a scroll or a spell). Do that, and you've got something that will be almost impossible to take down as long as there are enemies to fight. And you can't do that with any other class.
With a paladin, you can pick items, abilities, and talents that synergise with Flames of Devotion, which will give you the nastiest alpha striker of any class. Or you can build on Deep Faith, which will give you the highest defences by a pretty wide margin, while retaining a broad range of extremely useful support abilities (auras, exhortations). And neither of these will play like any other class.
Similar paths exist for fighters, monks, and rogues too (although personally I haven't played with rogues much; they require too much micro for my blood). Check out the builds thread on the Obsidian forums. Picking stuff that synergises with the class's core abilities is the whole key to it.
