@do.ob was quicker, but since I was already typing, here's my answer:
It’s possible that Favre’s requirements for that other winger position didn’t fit Pulisic well. I agree he’s been inconsistent, but he’s also had some great performances. The fact that they have sold him means Favre doesn’t rate him and wants to invest that money in other players.
Like do.ob said: No issues with player type, imo.
It’s bizarre that they are buying more midfield attacking players when Alcacer hasn’t been great since his red hot start
Creativity is a problem for every side that faces deep defenses on a regular basis. I don't think it's bizarre they aim to strengthen their top end and depth in the attacking department. Surplus players will leave.
What happens at the striker positions will propably depend on
a) what they expect from a fully fit Alcacer
b) how much potential they see in Isak
c) if they see Hazard as an option there (which I think they might)
d) their assessment of Götze (including his contract situation)
I can imagine a high profile transfer (young top talent), but I also wouldn't be surprised if they decide to simply upgrade their depth and further develop what they have.
Burki is a bit suspect and they are playing Weigl at CB. Wolf isn’t a real RB. Hakimi is on loan. Their issue this season is too many costly defensive errors.
Bürki has been outstanding this season, among their key performers along with Reus, Witsel, Sancho imo. Weigl started the season as their fifth CB option, he played because of injuries and then because he had some good games. GK and CB are settled, the only question marks are on backup level (Weigl/Toprak - possible transfers; Balerdi - immediate performance level).
I'm sure club and coach see the main solution for their defensive issues in better organization, the continued development of their talented, but young & relatively inexperienced players, and enough quality in depth when starters are injured. Plus fullback positions.
But given their recent results and the chatter in the market, it seems they are strengthening in areas that are already strong and ignoring their serious shortcomings.
Chatter so far suggests to me they have been looking at exactly the right places: fullbacks (Schulz), CM (Eggestein, although he chose to stay at Bremen), forward line. We'll see what eventually happens, but my guess is they'll buy 1-2 fullbacks, 1-2 CMs, 1-2 wingers/forwards, partly depending on who will leave.