There aren't any extreme balance issues in 5e. I don't know why people have this weird idea that balance is all over the place.
Personally, I think it's FANTASTIC that some people think that 5E's balance is all over the place. Because it means that those players have played enough of the game to come to that conclusion, and it bothers them enough to really delve into the game to the point where they feel not only that the need to "fix" the balance, but that they are going to go ahead and do it.
And when they do... they become better players and Dungeon Masters by actually working at the craft to make the game what they want it to be. They become more adept at "Rulings, Not Rules" because they are constantly looking at what they feel doesn't work, and then making their own rulings to correct the issues.
Then a little while later on... they become SO adept at fixing and changing things that don't work... a lot of times being able to do it on the fly as it comes up... that pretty soon they are experienced enough in the game to know that a lot of stuff that used to matter, doesn't really matter to them anymore.
The extreme balance of 4E accomplished two things... it made it such that new DMs could pick the game up and run it straight away with very little concern of things blowing up at the table... but also made it such that DMs had many fewer times where improvisation and learning how to "fix things" were necessary or important. Which is a skill that all DMs have to learn sooner or later, especially once you expand out from your starter game and start trying to run other ones (whether that be another edition of D&D or another RPG in its entirety.)
Once you learn to recognize that a game element isn't as balanced as you think it should be, *and* you know how to fix it so that it is... congratulations! You've leveled up your DMing skill. And you and your table are all going to benefit from that.