Limit Break Dancing
Never played 2E; I went straight from BECMI to 3E. That does sound more lenient than BECMI, for sure.Wanted a thief with better weapons? Multiclass or have the stats to be an assassin.
Want to be a fighter who casts spells? Demihuman multiclass, human with the stats and levels to switch class, human with the stats and levels in paladin or ranger. In 2e there was even a specialty priest of a sea god who had all the mechanics of a fighter plus a little bit of priest spell casting.
The red-box Basic Rules had an even easier approach: they baked in a lot of the top multiclassing choices into core classes. So if you wanted to be a thief with better weapons, play a Halfling. And if you wanted to be a Fighter who cast spells, choose Elf or Cleric. Even today, years later in 5E, I still prefer that approach. At Session Zero, if one of my players wants to multiclass, we will work together to create a single new "core" class to accomplish it. It's not nearly as difficult as the internet bogeymen would have you believe.