No, it's still relevant because "evasion" is the prerequisite for whatever prestige class, say fochlucan lyrist. The dweomerkeeper's prereqs are worded in a more vague way, so talking about the "evasion" class feature gives us a baseline for determining what it means to qualify for a prestige class.
Once we have a baseline, I'll be able to evaluate your wizardly comments.
In terms of "steps away", I think that's an irrelevant argument, but what matters is the difference between the potential for meeting a prerequisite, and actually meeting that prerequisite, which is what whoever it was was garbling.
BTW, I may agree with you that a wizard who has cast all his spells no longer qualifies (I'm not convinced yet).