Deconstruction time!
Mearls wrote:Summoning Demons
A variety of summoning spells throughout the game's history has allowed spellcasters to bring creatures from the elemental and Outer Planes to the Material Plane. That's a part of D&D history we want to keep, for sure, and we're not particularly excited about having people summon celestial badgers or fiendish piranhas. We think calling a creature from the Outer Planes, particularly, should be a pretty big deal, and it should get you a recognizable celestial or fiend—something you can find in the Monster Manual without adding a template.
I'm... pretty OK with this, to be honest. Celestial Badgers are pretty much a low point of summoning spells. Manes, Lemures or Imps are a fair bit more intriguing for that level of power
Now the meat:
But summoning a vrock or a bone devil is not easy. Well, bringing a devil to you isn't necessarily hard, but getting it to do what you want it to do is trickier—you need to give it something as well.
Ok, makes perfect sense. Do-able, but you have to come to some agreement with even moderate tier summons. Fine.
And summoning a demon requires a messy blood sacrifice, so you're not going to do it unless you're really evil.
For a given value of evil, I suppose. A lot of potential stories are being written out with such a simplistic black/white view. People stumbling blindly or naively into demonic bargains has a lot more narrative weight than red dots summoning bigger red dots in the flickering torchlight
It's easier to bring something like a modron or slaad, a yugoloth, or a gehreleth (demodand), and there are fewer strings attached.
Uh... what? No, seriously, WHAT? First off, this further marginalizes the neutral evil planes (again), and pisses of the backstory that they're the really hard core mercenary faction and consummate bargainers.
Second, and more importantly, if dealing with any of these creatures is easier AND has less of a penalty/price, why the FUCK would
anyone bother with demons/devils? Especially since the list of critters is almost entirely inclusive of being that won't shy at getting their hands dirty if you want to bad stuff for power. (Modrons being the exception, unless, of course, you can convince them that the result is more orderly, hierarchal or mechanistic, or that you'll do such a service in return).
No matter how many worlds you have (and there is still space for a lot), only the biggest idiots ever are going to summon Yeenoghu rather than Bob the Second Tier Modron to achieve their goals. Because he isn't likely to pop the heads off the cultists as step 1, and has plenty of power for step 2 and beyond.
