Okay, let me lay out an explicit example that shows why I think this is a bad idea.
On one side we have a standard npc 7th-level rogue with this feat and a few dogs (who are only there to stop the fighter from moving forward). He has a sorcerer buddy.
On the other side we have a 20th level pc fighter. He starts in a corner so he doesn't have anywhere to back away to.
Rogue wins initiative, moves in, uses this feat. Sorcerer hits fighter in the will save, either confusing, holding, charming or dominating him.
Fighter can't really do anything about it. He twiddles his thumbs. Maybe he punches the rogue in the face, but the rogue doesn't care; it's better than getting killed by a full attack for 100+ hp in one round.
The second round, well, the same thing happens. If the fighter keeps resisting the will save stuff, maybe our npc sorcerer starts shooting lightning bolts, scorching rays and magic missiles; whatever, a sorc ain't running out of spells any time soon.
The fighter, meanwhile, twiddles his thumbs some more.
Rinse and repeat.
What you're proposing is something with effects on the target almost identical to grappling, but irresistable. It's a way to negate a fighter-type with no trouble, no check, no nothing- and both in terms of the description of it and the effects of it, it sounds a lot like grappling.
Sorry, I can't see allowing this, ever, under any circumstances, in my campaign. Compare it to Improved Grapple: this one is far superior. Compare it to Improved Disarm: this still comes out on top, and is easier to get.
This may sound like a cool idea, but just picture your character on the receiving end and you begin to see why it isn't. It either totally nerfs the fighter or forces him to move.