I would say that the "classic razor" would be the archetype of razors, meaning, the razor that is immediately idendified as a razor beyond any doubt by anyone who is not a razor specialist. For instance: a W&B might be a classic to us, but the barber's notch would be a little too much... a spike point is elegant but there's something "wrong" on what concerns the archetype. Because of so many images people have seen in movies, photos and whatnot, I'd say that the archetypical razor is a 5/8 round point, no matter where it comes from.
For me a "classic" is no more than a benchmark for whatever it is. But mind me, the perception of archetypes and therefore, the perception of classic status - a symbolic value atributed to some object - varies a bit, despite the fact that an archetype does not vary in it's essencial lines. That's what an archetype realy is... but whatever involves the atribution of symbolic values is not ground as safe as the previous one...
Everybody knows what a razor might look like (excluding most eBay sellers... they don't have a clue!) meaning, if someone is asked to describe a razor, they will describe, more or less, the lines of the western razor (that don't change much from model to model or maker to maker). Nobody in the western world would describe a razor that fits the looks of a japanese style razor... I guess. This creates an archetype... but the definition of classic, being both an atribution of symbolic value and the benchmark for the definition of what a thing has to be (either as a whole or as a strating point) is much moe complicated and it takes someone who is a bit more knowledgeable to define a classic for himself. And others might follow his ideas... or they might not...
So, to me, there's an archetype. And I can add my idea of a classic razor: a 5/8 spike point. Maybe with tortoise scales. Why? Because a classic has to be a bit more than the archetype... it must raise it up a notch but keeping in mind that a classic is precisely that: a classic... meaning deportment and style and constitute a safe choice wherever, whenever.

Hope this confuses the hell out of you! I got a bit confused, I confess...