Oh, very true, but you do see how this particular combo can be easily abused? Heck, it doesn't really require the Fighter to stand anywhere special to be effective - if the squishy stays in the rear adjacent square, then nobody is going to be able to get close to him without the fighter being able to Tide and reposition.
It makes the Fighter a little too good at his role, in the same way that the old stealth rules made Ranged Rogues a little too good.