Seriously. You're basing half your argument off of one error last night (an egregious one, no doubt, but doesn't define his whole body of work). MAT has range that Span did as a younger player. The last two years here (and this year with SF), he's was/is a shell of himself in the field, range wise. I've never thought Span had a plus plus arm, but MAT sure as hell does. The issue you have seems to be instinctual. I don't see him taking a ton of terrible routes. I think he knows he has the speed/arm to make plays that most can't, and that aggressiveness can be a downfall, I guess.
I don't feel like getting into this debate, because I do think Span is a fine CF. I also think MAT is. His bat is a completely different story.