A sway bar has some play to it at least, plus it is closer to the front wheels. I just use my sway bar as an oil pan protector. A skid plate is only another thing that sits even lower than everything else, and unless the heads of the mounting bolts are recessed somehow they usually shear which makes the plate a pain to get off.
Something similar to the Tanabe brace but arched up instead of forward would be neat.
I am not really too bothered about stiffening the front though.