For me, no question a short course is preferable, but I think a practice range would provide more value to a club. Adrian is right, the par 3 courses I come across in the UK are generally dreadful -in fact - I haven't seen a worthwhile par 3 course over here. If more thought and money were poured into these projects they may do better, but its a gamble, especially as nearly always, the money could be used on the main course. If money is tight, I wouldn't even contemplate a short course.
Ciao