Yeah, Hernanes is great. I think he's suffering partly because Inter are so poor, partly because he's been moved forward a bit in the field. Their 4-3-1-2 system is a bit unconventional and, to my mind, doesn't suit him.
He's 30 in a few days, but I wouldn't mind taking a punt at him if Arteta leaves this summer. He's a similar player in a lot of ways, but quicker.