As usual, I will simply note that WoW certainly did not invest the concept of tree-based feat training--in fact, this methodology has been around for ages in a plethora of RPGs.
That aside, the true nature of a system like this is always in what it facilitates and how it functions in terms of character development--not that it is an array of icons in a tree shape with dependancies.
The fundamental difference between our feat trees and, for instance, WoW's talent trees is the fact that, in WoW, talents are generally used for defining your character on a fundamental level--whereas in Conan, feats are used to tweak your character in certain directions, without changing the fundamental playstyle of your chosen class.
For instance, in WoW, you have "Arms Warriors" (i.e. PvP Warriors), "Fury Warriors" (i.e. PvE DPS Warriors), and "Protection Warriors" (i.e. Tanking Warriors) and never (or rarely) the twain shall meet. If you spec deep into a tree, you are basically deciding how your class is going to play, or what your "virtual class" is. So, in WoW, your spec IS your class, in essence.
For our feat trees, we wanted something a bit different... we want decisions to matter, and for one to feel like they have an impact in their character's developement, however we do not want to change classes on a fundamental level. A Soldier should ALWAYS be able to tank/DPS/PvP in a general way as defined in the core class design, regardless of what points are spent where.
In that sense, having the Dark Templar feats as "Spells" and "Combos" with a mix of various utility, tweaks, and enhancements spread throughout makes for meaningful and interesting character development without sticking your character into a one-dimensional pigeon-holed role.
We also feel that having a shared Archetype tree where core role-based utility can reside helps facilite a feeling of being able to tweak, enhance, and learn character-specific abilities while also having easy access to core utility improvements on a general level.
I've been playing a new Dark Templar from scratch on beta recently to test out the feeling of the new feat trees, and honestly I like them a lot. They give me a feel of being able to tweak my character how I like, without making me feel like I "must" go into a specific tree. Of course people will ask, but I doubt you'll see: "LFM Depravity Dark Templar PST" type stuff... all the trees have cool things in them and "should" be equally viable in a wide range of situations. That is what makes our trees different from WoW and why a direct comparison isn't really possible.
Realistically, the end feats (of which there are 2 in every tree, with 4 "mid-tier" stand-alone feats in every tree as well) are things we have tried to design to be cool and fun, but never class-defining in a fundamental way. All the Dark Templar ones are arguably useful for various purposes in PvE Tanking, PvE DPS, and PvP. This isn't a situation where if you aren't Dread Shadow spec'd or Ravenous Eater spec'd you will suddenly find yourself unable to perform the various defined roles of a Dark Templar in the context of the game. Pick the ones that suit your playstyle and preference.
Forums, 8th November 2007 (Jayde) 
You customize your character mostly with Feats , binary abilities that let you access various powers or abilities. They can unlock your ability wear armor, cast spells or do special moves. There are more than 14k different feats in the game, all sorted by Class, race, featline and level – so there is no doubt a massive and deep system for the player to be able to customize his character. We have a clear goal to let all characters look, feel and play differently from another. Our visual character customization will go hand-in-hand with our RPG character generation and hopefully make many, many distinct classes and characters. Funcom is known to let players really customize their characters, and have a real choice in how they build their characters.
ShackNews, 16th June 2006 (Gaute Godager)