I don't think you've been watching or understanding Dier's play - you pick.Sissoko is not good enough for where we aspire to be. Having said that, he has been different class this season. As a footballer he has his limitations but he is self aware enough to know this unlike Dier who thinks he’s a better footballer than he is. Dier is an excellent utility player but I don’t see why some need to build him to some Pirlo esque, all conquering, ball playing CM when in reality he’s a destroyer, similar ironically to Parker who Sissoko and Wanyama get compared to.
He'll never be a Pirlo but he controls the game and the ball significantly better than the others. He has a far greater understanding of how the game is over the medium term in match, in the immediate setting and of how we play.
He's much more like Carrick than people give him credit for. Funnily enough, I used to have this same argument on here about why Carrick was a better option than his more highlight reel friendly alternatives.