RPGMemes

I don't think it's great for any class to take back powers that the character has earned. Not even clerics. For as long as there have been religions, there have been schisms and power plays. It even ruins possible intrigue involving religions if you can tell what follower of a good god has gone astray by asking them to cast a spell.

There are more interesting ways to do consequences for defiance of higher powers than to hold their abilities hostage. That feels less like the consequences of a living world, and more like the DM yanking the player's leash.

But I can accept that this is an established system/setting thing for clerics and paladins. For warlocks, it is not.