You mean at Everton, which is the basis for your opinion.
To me, if you've shown you were a very good player for over 200 games in the German and English top flight and led his Iceland team to the Euros and World Cup, 27 mediocre games in our awful side last year with no striker and almost no supporting cast - he barely played with Walcott, Coleman, and Cenk - and being asked to play a deper wing role to cover for Cuco Martina doesn't make me think he's not a good player. Quite the opposite.
But you and others think the 27 games makes him medicore. Maybe I'm a little too well versed in statistical sampling and actually watch a lot of football outside of Everton, but I think that's just silly.
Much like Ricarlison was great the first half of the year, but when asked to defend and work like crazy when you've been playing football consistently for over a year, I think there's a pretty good reason for him to have slowed down a bit.
Doucoure has not much to do with Siggy, but my opinion on him is what I've seen in the PL, which is the same league Everton plays in last time I checked. He's fantastic. Pace, power, skill, touch, great in the tackle, covers a ton of ground, good passing range, amazing transition player, good in the air, strong on the ball, good decision maker, excellent shot, opportunistic, he's got everything IMO.