The issue is: There will always be a problem for a group that plays with segregated pillars and uses a single frontman. Why?
Because if you play a frontman, and direct your character creation resources to be the frontman, but someone else does it with a +1 better bonus, oh well, sit to the side and be quiet.
So even if they propose to "fix" the fighter, and give them great social skills - they still will not be as good as the bard. So the phrase will be: "Hey, we fixed the fighter. But you still have to sit down and shut up because the bard is still a bit better."
When you do not mix the pillars. When you do not have organic conversations. And when you do not allow the game to be played per DMG and PHB suggestion, then you will - and can never - "fix" the game.
If you do, do those things, the classes play just fine.