Regarding White Dragon Lineage, I'm gonna have to side with SorO. "Similar to" doesn't mean "as if using" or any other language that sets up a rules dependency. Since its actual mechanics are actually not very similar at all, what it tells me is that the authors had this fluff idea in mind and had to insert that text to ensure the readers understood what they were trying to do. That they pointed out ways in which it is different from rage is reminder text, essentially. "Remember, this isn't an actual rage, so this particular thing we remember about rage isn't applicable", rather than a complete list of all things that differ from rage.
Best case scenario for the trick, it's similar to that Mind Blast feat that tells you you can channel power points into it and then gives you no rules for doing anything of the sort. They tell you it's similar, and then completely fail to tell you how. Then "it acts like rage" becomes a plausible interpretation of RAI. On the other hand, I can't in good conscience insist that rules that make a Rage Mage better are entirely unbalanced, although this interpretation still seems like it heavily favors full casters who dip a level of barbarian. Rage Mage is still terrible due to lost CLs.
