I think 4 is alright (Keeper and three proper footballers)Its up to fifa though.
wtf?
FIFA have nothing to do with only 4 subs. It's an A-League rule, and a useless one. Most (if not all) of Europe has 7. FIFA competitions have 12 (all the squad).
I think the finals series has 5 (though it may be 7). It's more than 4, whatever it is.
There's no magic number of subs (according to FIFA).