He had some good games at Udine as well, he's clearly talented. Wouldn't be against it, he's miles better on the ball than anyone we have for the position, might be problematic though that he's a left sided centre half like Koscielny who we'd look to pair with him.
Would be risky given his injury history but to be fair that's because the charlatans that are Bayern's medics have repeatedly mishandled his injuries just like they did with Thiago, Martinez, Robben and many others, they make our medical department look like high end professionals in comparison. Benatia had virtually no history before his move to Bayern, of course there's always a risk involved giving that he'd be signing for Arsenal but I'd try our luck, not like there are many other readymade CBs around and from the sound of it he should be around 15-20m which is decent