That's actually a really good idea. It would be nice if creative teams had a framework to work within. I was re-reading some of X-Factor and there was all sorts of loose ends because all indications were they didn't know they were being cancelled. Hell, they seemed to still have plans for Wildchild after issue #142, which effectively ended up being his extremely depressing last appearance in the title. If they knew how much time they had left, they could have planned, and he might never have ended up perfect fodder for Tierri. ;_;
I'm pretty sure it's NORMAL for first issues to have unusually high sales. Collectors. If Marvel was going by the first issue's sales, then they're even bigger idiots than previously stated.