Armor stands weren't handled well - if a player directed an armor stand,
he may come back later to find some other items like paintings for
example missing. Now if at the limit, no placing new armor stands or
interact with (putting items on) existing stands.
Much easier to understand and customize, especially for server owners
who are new to GP and have both survival and creative worlds. Also, a
performance improvement - when claim creation is disabled in a world, GP
will not protect any existing claims in that world.