My issue with this, or at least one issue is that we're focusing on one character and not the group. For example:
If Fighter + feats + cleric action = 100
What does
Fighter + feats + the action of another character equal?
If that second equation is close to the first then there is no real balance issue. After all the group is doing similar damage and is equivalently effective. After all, the second equation leaves the cleric completely free to contribute.
It's only a problem if the first equation cannot be equalled by the second. And there is some wiggle room here. If group 1 defeats an encounter in 3 rounds and group 2 takes 4, do we really care?
I'm not convinced that there is that much disparity between the two groups.
No.
It's Fighter + Feats > Sorcerer || Evoker || Barbarian + Feats.
Fighter + Feats > Paladin + Feats over the course of a day.
Fighter + Feats >> Fighter.
Fighter + Feats >> Rogue.
Fighter + Feats + Bless (insert other effect here) >> Sorcerer + Fighter.
And
Fighter + Feats + Bless (insert other effect here) > Monsters Manual = DM workload++
Now whether or not that is an issue or not depends on these factors:
If your group is new (DM including), and you have a player who has read about these things on a guide, you're going to have a problem.
If your group are optimizers and the DM is new to 5e, you're going to have a problem.
If you're running an official AP and don't have time to tweak it you're going to have a problem.
However:
If your group doesn't go beyond level 8-12 you probably won't have a problem.
If your group doesn't group optimize you probably won't have a problem.
If your group (DM included) doesn't care about one single player totally dominating the combat pillar of the game you probably won't have a problem.
There are no conditions however in which these feats never cause a problem ever. They either cause problems, or do not cause problems. The mere fact however that there is the potential for problems means new DM's especially should be wary of them.