Salthorae
Imperial Mountain Dew Taster
Obvious question: What kind of game gives you a choice to be more powerful, and then expects you to not take that choice? That seems like a critical design flaw, right off the bat.
This game gives DM's a choice to decide to allow the PC's to be more powerful, but is designed more simply, around new players coming D&D who know nothing about legacy concepts like Feats. 5e is designed to allow them to read just the basics, play a single class and have fun. Then when they have some experience they can play around with variant options (Feats).
If a DM allows players to take feats and/or multiclassing and assumes that the base designed game around encounters is doing to stay balanced with PC's that are now more powerful, then they are missing part of the equation. It's basic math to me. The base game is x+y=Z, add in feats/multiclassing/variant humans and now you have 1.5x+y<>z