Sorry @MechaTarrasque gonna agree with @Phazonfish here - you cannot call it good design to offer a spell that's designed to force outsiders to do your bidding, but not then ensure a reliable supply of such outsiders.Any outsider that agrees to sitting still for a whole hour doesn't need to be bound. So that can't be the use case.
There must be a way to pacify a hostile outsider long enough to take control over it. That's what the discussion is about. If there are no such ways, then Planar Binding sucks.
And that assumes you can even find such an outsider. In every edition past, you could always conjure up your own. If that isn't possible in 5E, then Planar Binding sucks even more.
As for stories involving outsiders - if you don't need a spell to summon the monster, it's reasonable to expect you don't need one to bind it either. So what's the spell even for?
Perhaps there once was more support for summoning and binding of outsiders, but Planar Binding certainly isn't good enough on its own.
Right now, it all looks towards Planar Binding being essentially worthless unless we can come up with a way to arrange the conditions it requires. Have anyone tweeted the devs about how they suggest we use it?
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