There will be no change once they will come from world cup. the only thing that will give a huge change is once some players from arsenal will be bought by another team. this will force arteta to make a new rotation and this will also change his strategy for arsenal. There will be lots of change to happen in the europa league next year. im sure that if we will see so many new names come to the various club that participated in the europa league. it's potentially to see the new name that will come to the barcelona as well. it's just the matter of time as so many club and arsenal have been making some preparation.
I do not think that Arsenal players could be bought right now, thats not possible. First of all Arsenal is a rich club already, they are a leading Premier league team and that gives you a ton of money to begin with, secondly they will earn a whole ton more because winning or even being second would give them too much money as well.
So, they really do not need the money asap, it would be weird to sell players at this point of the season, if they really really want to sell then they could end up selling during summer and still make a lot of money, and players form the club that became champions in premier league would worth a lot more than a team that is "leading" the premier league at half of the season.