He really hasn't. He had that brilliant spell from, what, September to early December last season, and hasn't hit the same heights in either goals or assists since. Go on Twitter after any Newcastle game, you'll find loads of their fans expressing frustration with him or outright slating him...
Good god, no thanks. He's like a Paraguayan Craig Mackail-Smith.
The funny thing was, Grealish got pissed on holiday two years ago, compared one of his team mates' performances unfavourably to Almiron, and Newcastle fans all hit the roof, even though they all knew deep down he wasn't very good...