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.
