Mourinho did love Fellani through so does have a thing for weird players lol...
(although I think Fellani has a lot more ability than Sissoko tbh, he’s just not your typical pretty footballer in his style).
Fellaini was a solid, versatile, hold-up player with aerial abilty and an attacking threat. Mourinho used Fellaini's versatility to both chase games when Utd needed a goal in an attacking sense, or defensively, to close games down with an aerial outlet that could also protect and distribute the ball effectively. Fellaini's aerial strength gave Utd attacking and defensive options.Fellani scores goals though.
One thing is for sure, if Jose can get Sissoko not to forget how to be a professional footballer when he gets near the oppositions goal then he really is a genius.
Think Sissoko has a role to play, and definite strengths to his game, which he showed plenty of times last season when he was pretty much our only ever-present CM. I think he is defensively under-rated. With Poch's insistence on the diamond, he was mopping up opposition attacks in CM and on both flanks. I thought he was our best defender in many of those games.
One-on_one, he isn't often beaten for speed or strength by any attacker, and he's hard to stop when he's surging forward....unless he comically trips himself.
I get the criticism of his positional sense/awareness to cut it as a holding DM, but still there's enough to do the job if need be.