I know he's had some selection dilemmas with injuries and fixture congestion but hopefully Allardyce has figured out what our best system is by now. Every time we've played well, it's been in this 4-3-3 system we're seeing today.
I think the bolded areas are the ones we need to prioritize in January. Left back is an unquestionable area of need. A new CF is nice (and it looks like we're getting Tosun) but I don't think it's nearly as important as upgrading the midfield. When Rooney or Davies miss a match, we offer absolutely nothing on the ball through the middle. We need midfield reinforcements and we should be prioritizing players with creative passing ability or transition dribbling skills.
It's possible that Sigurdsson could help in the middle. I don't see it with his open play passing, and he's certainly not a dribbler, but I'm open to the idea. Maybe Barkley comes back and gives us another option. Who knows with his situation? The only thing I'm certain about is that our next midfield signing has to offer something significant going forward. We have plenty of solid defensive midfielders who can regularly nail straightforward passes and we generally play awful football when we use any of them together.