I am absolutely in sync with your last paragraph...those are my positions throughout the discussion.
I think we're talking about it, not because it isn't straightforward, but for the very simple reason that some segment of the comic collecting world is trying...for reasons of their own...to reclassify "first appearances" as the first time any character appeared in print, in any format, regardless of the source and regardless of the intentions of the publishers, redefining previews and ads as "actual appearances", despite the lack of sequential art that is the foundation of the artform.
That is the fundamental problem.
An ad in Previews magazine, for example, showing Rick Grimes on the cover of Walking Dead #1...several months before it was published...and the logotype for the title hadn't even settled at that point...that is now being pointed to as "the real" first appearance of Rick Grimes.
Such way lies madness.
Indeed, madness. The unfortunate thing is the motivation is $$$. But to dilute what took so long to evolve is sacrosanct.
(Kind of like pressing to get a higher grade, or micro-trimming, or spine realignment . . . )