The problem with earlier versions of D&D is simple math: a level 20 warrior will get a whooping +20 to their attack. And you dont have any ability to gain +20 to your armor class; not even close. Thus warriors will effectively ignore your armor class and hit you all the time.
Which is not a flaw in the system of having Warriors scale better than other martials (Who would get +15 attack from BAB or Sorc/Wizard who'd get +10 attack from BAB) but simply a flaw in scaling defence in a similar fashion.
The reason I mentioned BG2 and KotOR is that I have played both games to the death and know them very well. The problem also appears in all other D&D games I've played in the past, provided they would progress to higher levels.
I don't think it appears in all other D&D games... Most D&D games, like with KotoR, you could get ridiculously high AC's too. 50+ AC is not unheard of in many d20 based games. Which is not by any means, negated by a mere +20 from a Warrior BAB (Even if you include things like +5 weapons and 20 STR that's still only +30 attack leaving you with 20AC for a regular d20 min roll of 5% chance to hit with a nat 20)
In D&D5 you can now only gain +2 at level 1 to your attack, in BG3 culminating to +4 at level 9, and in the original system to +6 at level 17. So your total gain will only be +4.
The real progression is of course different, because thanks to other mechanisms you can gain attack bonus from other sources - feats, gear, and in BG3 especially strength elixiers. And in BG3 specifically the broken feat Tavern Brawler completely breaks the logic into pieces. But opponents never use such broken mechanics.
No, opponents just get randomly boosted attack rolls when playing on higher difficulties (Or if they're bosses)
While simultaneously, you have also very few ways to boost AC to compensate. Like, all you can really do for AC is wear a shield, some medium armour (That bypasses the Dex bonus cap) and stack Dex out the wazoo.
On Honour Mode its impossible to get capped AC to minimize later game bosses hit rates to the minimum 5%.
It's never down to the system of how attack scales, but how both attack and defence scale.
The other reason why D&D5 is to my mind a huge improvement over previous versions is that many more spells than traditionally use attack rolls, even for spells. Thats why spellcasters have to focus on getting higher attacks, too, though I dont know of any feat that would help and theres no Tavern Brawler for them, theres only items.
Ehh... Spell casters still just stack spell DC like always, which converts into attack roll bonuses for attack roll spells.
The only new thing in 5e is that Cantrips are actually worth using because not only are they a relevant attack, but they also scale their hit die with levels. Meaning casters don't have to run around with a crossbow to use when they're out of spell slots (Which given that crossbows didn't used to scale off any stats, meant that things like BAB was even more relevant to actually hit with the things)
BG3 has a multitude of ways how to get better attack on opponents. You can blind them, you can make them fall prone, you can stun them, etc.
And in this case, spellcasters will also benefit from these conditions for their spell attacks.
Which is literally no different to prior D&D editions. All these effects existed before 5e and most casters were literally based around applying them (They were called "Save or Suck" spells for a reason. Enemies had to pass a save check and if they failed they became completely debilitated or were outright instantly killed)
The only difference is with prone. Where before ranged attacks got a penalty from trying to hit a prone target (Which included spells with attack rolls)... But before you had Coup de Grace so leaving an enemy helpless could allow you to insta-kill them with a martial.
This is an advantage that no spellcaster can have. So much so that it is a simple trick to as a rule give spellcasters two Hand Crossbows for a ranged weapon just so they can always use their bonus action for an offhand attack with their second crossbow.
Sorcerers literally get Quicked Spell metamagic to allow them to cast spells using Bonus Actions.
