As an aside, I think target restrictions are actually pretty huge, worth approximately three spell levels. Compare Hold Person (2nd level, scales) to Hold Monster (5th level, doesn't scale), or Dominate Person (5th level) to Dominate Monster (8th level, longer duration). You can paralyze 4 humanoids for the same 5th level spell slot as one crocodile.
I agree that Broken Will is also different, and the one-round duration plus immunity-on-save is important, but overall I think it's clear that psionics really is better at mind-control from a pure power perspective. A wizard trying to get an adult red dragon to claw itself to death has to spend an 8th level spell slot and overcome a Wisdom +7 saving throw, and the dragon gets another saving throw each time it takes damage, so in order to get three successful attacks in for 50-ish damage, he has to beat THREE saves at +7 after exhausting legendary resistance. It could happen but it's not likely, and it's expensive. A 5th level telepath on the other hand just has to spend 5 PP and beat one Int save at +3. (Interestingly the telepath doesn't control the dragon's bonus action or reaction, but vanilla dragons have no real use for their bonus action so it doesn't much matter. My dragons are all sorcerers with Quicken Metamagic so it would matter a lot at my table.) A party of mid-level Telepaths, Diviners, and/or Wild Sorcs would have a very good chance of getting a dragon to claw its own self to death via Broken Will, which would never ever happen via Dominate Monster.