I feel that the crossbow damage nerfs in the past were a bigger deal than increased strength requirement.
I wouldn't want to go below 12 strength as a crossbow build, personally. If I was using the regular crossbow I would want to be capable of melee combat as well, and strength below 12 is not going to work very well for that. Not being able to go 15/XX as pure arbalest build hurts more than any of the other requirement changes, but it still isn't a big deal. Crossbows don't require a weapon-specific skill like melee, throwing, and archery do. And the high end bows already require 18 strength.