of course a team will go through a long process to become stronger than what happened to them before. but additional players are the first option to improve the quality of the current team even we saw newcastle united also made a big improvement in the last summer window and it seems they are doing a better job now. West Ham will most likely be able to make improvements in the winter window because for now we see them to be in 16th place in the standings with a collection of points that are quite close to teams who are in the relegation zone.
Newcastle has always practiced well to improve teamwork which until now has been the key to victory for Newcastle, at least Newcastle has proven that they are capable of winning and there is still potential to win first place. It is likely that when the transfer market is open then Newcastle will try to add new players again to strengthen the team they have.
I would say the best teamwork we have seen this season is between the Newcastle players. In second place I will put Arsenal team. Newcastle have no star players. Newcastle have improved tremendously this season simply because of the understanding between the players and the confidence they have. They are able to play well in every match.
Now Newcastle need some very talented players. Newcastle's defense is very strong. They need more talented forwards and regular scorers. If Newcastle strengthen their attack in the next winter transfer window, then Newcastle's team performance will improve even more.