Faolyn
(she/her)
I'm not sure. A fighter's weapon attack rolls and a wizard's spell attack rolls are going to be the same (assuming they both have the same level in their stat). They're both prof bonus + stat mod. And anything the fighter has that requires a save is going to be the same as the wizard's spell save DC. (And the same thing for every other class as well). The only difference is if the fighter has a weapon that gives bonuses, since there are very few items that give spellcasters bonuses to their attack rolls.A 20th level fire bolt does 4d10 damage, 22 points and only 1 attack. A 20th level fighter, well it depends on a lot of factors but let's say a +1 longsword and 20 strength. That's minimum 1d8+6 damage for 10.5 and the fighter gets 4 attacks.
I'm sure other casters would do a bit more damage, but the fighter damage is also on the extreme low end. If we assume hitting 60% of the time the wizard averaging less than half the fighter.
OK, and there are probably more things that give fighters advantage on weapon attack rolls than there are things that give spellcasters advantage on spell attack rolls. But in general, a fighter and a spellcaster with the same stats and PB should be rolling similarly on attack rolls. It's just that the fighter has more attacks.
This is why I also suggested elsewhere that fighters eventually get weapon specialization. Apparently there's a 3pp called 5th edition feats which includes such a feat (+1 to attack, +2 damage, 1/short rest advantage on attack), although something like that should actually either be in the PHB core or even baked into the class itself.
I definitely agree about this--except that the 6-8 encounters isn't actually a rule or even a guideline. It's just a note in the DMG that that's about as many medium-difficulty encounters a typical party can endure before being completely tapped out. For some reason, people took that to mean that the entire game is built around 6-8 encounters per day, and that deviating from that number is unbalanced in some way, or even wrong.It seems like the biggest issue is the game being built around more than 2-3 encounters per long rest. If you know you can reliably go nova and cast utility spells and you don't use feats and you don't give non-casters magic items that help compensate some of their weaknesses then it can be an issue. I just think it's an issue that can be resolved in many ways. Not least of which is just accepting that there is no such thing as perfect balance and casters and non-casters are always going to have different roles to play.
Personally, I tend to fewer but tougher encounters. Combat and other resource-draining encounters are fun but if you had 6-8 of them in a day, that's all you'd be doing.