But I guess it all comes down to the art itself and on how it is combined with it surroundings.
That is basically what I was saying. I have books I like that are from most of the types mentioned above, so it really boils down to the art itself and how it mingles with the format of the cover. No matter what, they have to make people
want to pick them up - something I never did with the RM books; it took a friend of mine to introduce me to the game, as I never got past scanning them on the shelves when they first came out.
Chainmail bikinis had their part in the RPG industry, and while they are really impractical (I am looking at you Red Sonja!), you cannot doubt their influence on the hobby (again: I am looking at you Red Sonja!) - and thousands, if not millions, of teenagers. Some of the "best" were by Larry Elmore, if I remember correctly...
Personally, I do not like cartoonish art if it is to reflect anything gritty or "realistic." No big-eyes and small-mouths, thank you very much! And elf ears should not be so big and pointy that they shoot past the top of their head - that is just ridiculous. (Elves are not my personal favorite - I definitely prefer halflings and gnomes to them, and humans overall - but they have been, and will continue to be a big part of the fantasy gaming scene. So, we just have to put up with them, and try to make them as cool and interesting as possible. And not make them into anime elves.)