So why do the Doyle and Magie errors counts as part of the set?

[Runscott]

Interesting to hear the different perspectives on this.

Doyle and Magie were corrections - you can count them or not count them. There are plenty of other things that were intentionally changed, or 'corrected', in various cards, that don't involves the captions, and no one considers those to be different cards. And there are things like missing red 'B's, 'nodgrass', etc., that are just crappily-produced cards. If you are interested in such things, then collect them - I'm surprised no one has created a new checklist that includes all of these in it (even the odd Marquards, caps missing stripes, etc - anything released to production and not a scrap).

My list is much simpler - I want at least one of each player (one Cobb, one Chase, etc) but multiples if I like the design a lot (all three Matty's). Not sure what the length of such a checklist would be, but it's simpler and cheaper to collect the 'mini-monster'.