The current implementation of the !crawl function doesn't make a great deal of sense.
As it stands, you get +3 armor class to all attacks, and a move speed debuff. The move speed debuff can be negated by freedom of movement, which means it is just three points of 'free' armor class.
The p&p interpretation of crawling is that it gives you +4 AC vs ranged attacks, -4 AC vs. melee attacks, and -4 attack with melee weapons. Additionally it requires an action to stand up from crawling.
If people had a crawl widget (item's special power self only) that required an action to use and toggled crawling with the p&p modifiers, it would encourage more tactical use of crawling - people would benefit from crawling in certain tactical circumstances rather than all.