Well, I'm still working my way through the rules as time allows - almost done with the PHB. I still haven't had a chance to try them out in practice, and it looks like it will be a couple more weeks before I get that opportunity.
There was something that occurred to me, and I feel like I must be missing something or misunderstanding. As I read it, a standard melee attack role (to use an example) is 1d20 + proficiency bonus + STR modifier, regardless of class (and assuming proficiency with the weapon in question). As the proficiency bonus is the same for all characters of a given level, STR then becomes the only difference in characters' ability to hit a target. Doesn't this essentially mean that a fighter and a wizard with the same STR score have an equal chance to hit a target with a melee attack? Maybe this is how it is supposed to work, but it seems odd to me to base the ability to hit a target solely on a physical attribute without accounting for differences in training and experience - the fighter probably spent years learning how to hit things, while the wizard was probably sitting in a library pouring over dusty tomes. Maybe this particular wizard did his push-ups every morning, and on study breaks would bench-press stacks of spell books, but I'm not sure that should be enough to give him the same accuracy in hand-to-hand combat as the fighter. I've known plenty of physically strong people who did not know how to fight; training is always a factor.
Have I missed something? Am I completely wrong here? If not, how does it play out in practice? I realize that a strong wizard may be a rarity at most tables, but I've seen it a few times and it's not unheard of. I just think that relying on typical relative attribute levels to make one class better at combat than another is a bit short-sighted. I understand that the fighter does have other combat abilities on top of this, but the two fundamentals of combat are 1) being able to hit a target, and 2) inflicting damage on that target. Yes, generally speaking the fighter has access to weapons with better damage, but this only addresses half of the equation. If the two got in a fist fight, they'd be on even footing. The whole situation created by this mechanic just feels off to me.