As others have has said, he may or may not be a decent number ten but we won't know until he plays with a better number nine.
That was always said about CMS except we always claimed 'once CMS has a decent number 10 playing next to him, he'll start turning it on'. Once that number 10 was finally brought in (Ulloa) CMS was dropped.
I think we may have to define our terms here. Ulloa was a number nine in my eyes. CMS was a support striker played out of position.
All the new signings need a few games to get up to speed with all aspects of the premier.
I am thinking we shouldn't be judging players after three games. There seems to be a decision among some on here to criticise our summer signings already. Ryan should be replaced, Propper is terrible, Gross is too slow. In the same way you can't judge the league table until 10 games are gone, the same should be the case for new signings, especially ones who have never played in England before.
I look forward to post West Brom match when people inevitably write off our new striker(s) as they've not scored.