In defence of Sig and DCL and Kean we really aren't set up to score goals or create chances. Sig in particular has produced all his best football for us with Walcott in the team. The reason is simple Walcott makes runs in behind the defence and Sig is the best player at the club for picking them out.
As things stand currently Richarlison is stuck out virtually on the right touch line all game and iwobi/Bernard come inside all the time so the only creative option for Sig to pick out is DCL or Keam neither of whom seem to try to go in behind often.
When Sig drops off another midfielder needs to go beyond to give him an option and that never happens. Why we don't have Richarlison learning how to make the runs theo does I have no idea.
At Swansea Sig looked great because he had 2 quick wingers running behind and creating space but at the moment there's none of that. As a result it does feel like Sig should be dropped but I'm not sure that helps. I don't think anyone else can change things while we have no forward players or midfielders tying to make runs. Presumably this is also why we resort to going wide and crossing yo no-one all game long. We just don't have the players to interchange or create space in the middle. It's all slow and predictable but we don't have the players formation or manager to fix that.