Personally I didn't love 2nd Edition's multiclassing. And I found Pathfinder to be a swamp in terms of possibilities. I actually MUCH prefer the more basic system for Multiclassing in 5e by a mile to either (and I started playing D&D P&P with 2e way back in the 90s, so I'm pretty intimate with it in particular).
No one liked AD&D, after 3e was released.
PF1e is pretty much polished 3.5e. Generally simplified and optimised, but still hard to get into, if you not dedicated enough to study all rules.
PF2e right now pretty much a pinnacle of what D&D should be.
As of 5e, generally it's just a "D&D for noobs". And where there is appeal to it as well, it's also unfortunately heavily penalize any minmaxing expert of gaming.
You can both easily make creasily powerful character, that would handle himself easily through any combat encounter DM throw at you, without even worrying about group synergy.
And at the same time restrict you on what possibilities you would have as a whole. After a while you would either have to agree roll characters very similar to those you already played, or just move on to another system.
As a whole, you just can't make system that can be both very easy to learn, and very versatile at the same time. Any really interesting system requires study.
I actually looked at 5e as more of an attempt at merging D&D with a simplified system in the style of White Wolf (Vampire The Masquerade, Werewolf Apocalypse, etc.).
As a fan of those games over 2e and 3.5, and Pathfinder 1e I prefer the limitations (it makes your players more likely to build a party together to support each other instead of being everyman out for themselves/min-maxing in order to see who made the strongest character etc.
I much prefer simpler rules with a heavy emphasis on cinematic story telling and role playing without meta gaming.
Which brings me back to why I think Multiclassing is something that shouldn't be eschewed for BG3. Since most players will have a single player experience, you need to build a party around a main character who can do some of the social dynamics of a face, as well as have as much utility as possible outside of combat.
There's enough characters to avoid scum saving if there's a little overlap in Rogue Skills and at least ONE character is a strong Face.
But it's much harder to build that character without relying on a couple stronger races without the advantage of Multiclassing in order to net better skill lists (something I kept trying to impart on you).
This isn't to power game, it's just to make it easier without having to reload (there's a lot of traps for instance, and a great many social encounters).
So far any character can pick locks as long as you find Thieves Tools (which might get changed), but that means DEX heavy characters are much more valuable than Strength heavy characters for main.
Really this all boils down to Perception being the most valuable skill, and having one to two characters with decent scores in it helps to make things move much more smoothly. But the same can be said of 5e P&P.
Is it perfect? No, not really, but I'm also not sure that adding more complexity before focusing on role playing is ever a good thing.