I quite like having corners myself. I will often work with my young dog in corners, either corners of the pasture or corners of a night pen. He's very, very fond of holding sheep in a corner, or on a fence. (Once during a trial the sheep bolted to the fence, and he decided to just hold them there rather than fetch them to me. That run ended pretty quickly). It's been good for him to understand that yes, there ARE times when I *want* you to hold the sheep in a corner - but there are also times when I want you to peel them out of one. And you need to LISTEN and figure out which case this is! His grandfather was much the same way, I hear, and his owner used to regularly do some corner work before each trial.
I've got an awkward corner in my barn, adjacent to the aisleway where I pack sheep if I'm checking for parasites or vaccinating them. I've found it's more expedient to "round" this awkward corner off with some lambing panels. That way I actually end up with two holding areas for packing sheep, and no one is tempted to try to hide in the awkward corner. Works for me, and a whole lot cheaper than a fancy sheep handling system.