After reading this thread, I'm becoming more and more inclined to the idea that 5E should follow M&M 2E and HERO 6E's lead in removing stat modifiers from attack rolls and defenses.
But of course the question might arise - what's the point of having all these stats then, if they never affect anything?
And if they keep affecting things, what happens now?
Maybe one way to "balance" stats better would be a mix of point buy system and attack/defense system that rewards all combinations of stats, but in different ways.
For example, at the moment, the cost for raising a 16 to an 18 is 7 points. 7 Points could get a 14 and 13 in some other stat. What does this give you? Probably about a +2 to +1 spread over two defenses. Compared to a +1 to attack and defense.
How do we value attacks vs defenses? I'd say we value it higher than a bonus to a defense. The +1 to attack helps you against _every_ monster you encounter, the +1 or +2 to a defense against _some_ monsters you encounter. So, let's set the multiplier at x3. A +1 bonus to attack is as much worth as a +1 bonus distributed over 3 defenses. So, the 18 is effectively worth as much as a +1 bonus to 4 defenses (since it also imrpoves one defense, not just attack)
So maybe at the moment, the price is simply too low?
Maybe the sensible cut-off point should be 16?
Of course, it doesn't really change things. Now someone might ask a newbie: "What, your Wizard has a INT of 20? That's wasteful! You'll be hit all the time! What good is your attack bonus if your stunned or dead?"
although i must admit: our fighters always had 18 strength. 
