Justin D. Jacobson
First Post
There are a few things here and there that depend on the source of a power/whatever. The sorcerer's Draconic Power and Chaos Power class features, for example, boost any Arcane power, not just the sorcerer's own unique powers. And a wand's Daily power can be used by anyone that has at least one Arcane power.
These things aren't very common, sure, but I'd imagine we'll see more and more of this as more 4e books are published...
That is one of the clever bits of 4e's commitment to exception-based design. Right now, power source is a component without a mechanical role, but it can always be recruited later.
There does seem to be a strong correlation between power source and role. Martial classes generally have striker influences. Arcane/controller and divine/leader are also correlative. (This leads me to believe that primal will tend toward defender, which seems to be borne out in the previews I've seen so far.) Thus, you have Warlock, which is a striker but, being arcane-based, has a definitive secondary theme of controller. Compare fighter, which is a defender but, being martial-based, has a secondary striker theme with this big damage powers, e.g., brutal strike. Now, rogue and ranger are martial-based strikers, which means -- you guessed it -- they're extra-strikery. Clerics are super-leaders, wizards super-controllers, etc.
Power sources aren't just window dressing.