Minsc was originally a Ranger because of Marc's point, BG1 didn't have Barbarians. Due to that limitation the canon and fan stories kept him locked in as a ranger meanwhile class / ability purists were complaining why was he a ranger and not a berzerker subclass of barbarian.
The Ranger class does not fit MInsc's personality or battle rage personality at all, and its just one of things I've disliked about him being a Ranger being left as canon just because it was due to an engine limitation in the first game.
Now as with Jaheira, the level cap in BG3 isn't even the issue, 5e ruleset is. Even if you made her a 10 fighter / 10 druid or such she would never match the potential of an AD&D Fighter / Druid.
Using whirlwind attacks as a fire elemental was her entire 'Godlike' thing in BG2, it was horribly broken but then thats what made BG2 so fun, everything was broken with the massive EXP and level caps in that game.
And I think its because of this in BG2 that further rulesets and games continued the trend of making players less and less powerful. 'How dare you be as powerful and godlike as BG2 allowed??? Not in my game / new ruleset', yet completely ignoring the whole point of that power level in BG2 was simply that it was super fun and incredible to play.
So we will simply never have that level of enjoyment in any dnd game ever again.
