one could sit down and play WoW for the rest of one's life and, in theory, be perfectly happy about it.

Someone who is well-integratedly happy to play WoW for a lifetime sounds weird, but not akratic, to me.

As for whether, if the desire for WoW is a misfiring of the brain in response to some unconscious impulse that could be more efficiently satisfied by watching a space shuttle take off (for example), "need" is the right word to apply to the experience of watching a space shuttle taking off, I don't know. It doesn't seem like an ordinary-language-compatible use of the word "want" to call it a want (or by the same token a desire), so I appropriated the word "need" in much the same way one might use it to say "I need a hug" or "I need a minute" or "I need a cigarette" even when one's long-term physiological health doesn't depend on affection/time/nicotine.