So what you said- NATO is problem to Russia? or Russia is problem to NATO?
As far as I am concerned no-one(majority talking from member state) finds it problematic...
All I see, that anyone that is not in NATO might consider/willing to be in alliance.
Well alliances are two way streets. Benefits are usually not without costs. Every member state or potential member of an alliance should utilize a cost-benefit analysis to see if it is truly in that state's interests to join.
Some benefits of alliance membership include enhanced deterrence of an attack, or enhanced defense capability, etc. But the costs include the risk of aiding an ally, the risk of war entrapment, the limitation of options, risk of a counter alliance, etc.
You also have the issue of tethering powerful states within an alliance constraining their courses of action. So alliances are not always a universally good thing, even NATO.
In the case of Sweden joining, both NATO members and Sweden need to consider the pros and cons of that action. Sweden has historically been a neutral country, with some pacific tendencies. There is also the issue of Swedish domestic politics to consider. Do the people of Sweden want to join a military defensive alliance?
Lastly NATO states have to consider the issue of burden sharing; what does or can Sweden bring to the alliance other than another land mass to defend? Is its military readiness up to NATO standards? I don't know much about Swedish military issues so it is possible, though I have read that when several Eastern European countries joined NATO their militaries were not up to standards.
These are some issues to consider I think in answering the question of whether Sweden will join NATO.