From that John Byrne thread, this was a good way to go back in the 60s but I think clinging to the same "rule" now would be too limiting:
Stan Lee maintained that one should be able to pick a character out of a group based solely on his/her name alone, without any prior knowledge of that character, or anyone else in the group. Consider this shot of the original X-Men:
Try to imagine you have not heard of any of these characters before. Which one is Iceman? Which is the Beast? Angel? And which one looks like a Cylcops?*
Now apply the same question to the illustration on the previous page. Can you pick out those characters by name alone? Is there, for example, based solely on that drawing, anything to distinguish Cyclops from Magneto?