What is short? Most folks probably think recurves of 52" or less are short...and I do too. They have their applications, most notably for use in enclosed areas such as restricted blinds, tree stands, shooting from your butt, etc.
However, they are short range bows where shots are 20 yards or less. Yes, some folks can do well at farther targets, but there are more than one reason your competitive distance archers pick a 70" bow instead of a 48" one.
BTW, I believe Chris Hill takes a look at the advantages of short bows in the next issue of TradArchers World magazine. He is one of the finest shots with a bow here in my area, so I'm looking forward to his comments on short bows.