RFisher said:
That doesn't mean that it's wrong. (^_^)
(

) But doesn't readability directly depend upon whether it is blue on white or full color & which the individual reader finds readable?
Again, just because something isn't absolutely objective, doesn't make it subjective. Heck, I'm color blind, so sometimes maps are actually hard to read for me, but, come on, I would hardly fault a map designer for not taking that into account. There does have to be a bit of a "common person" standard applied.
If a reader is trying to read the map on a dark, cloudy night, with no moon, while standing in a windowless basement, also unlit, and then complains that the map is unreadable, this doesn't mean that readability is a subjective term, it means that the complainer is a prat.
Take the idea of robustness from TwinBahumut above. An excellent criteria. Does the module have enough flexibility after the dice hit the table. Now, what constitutes "enough" will differ from person to person, but, by and large, we can agree on the extremes. OTOH, take the recent threads about small corridors. For some people, small, narrow dungeons are a bad thing, for others, it lends itself to a level of verisimilitude. That's a pretty decent example of a subjective criteria, since it is unlikely you could come up with any sort of reasonable standard.
Again, sorry, writing off centuries of criticism just because its not absolutely objective is ridiculous.