Honestly, I really dislike the current save system, six are too many, and if you have a low save you're pretty much useless if the enemy is targetting it. I play a Wizard in a westmarch server, and had whole quests where he just spammed Tasha's Mind Whip nonstop since so many enemies have terrible Intelligence saves and will basically auto-fail.
Intelligence and Charisma in particular, there aren't too many effects that target them, but those that do can just annihilate you, and there are a lot of enemies with very low saves on those two, while at least Wisdom people remember to make good.
For players, they'll usually have a couple stats that are low unless they roll godly, and as the levels go up they can just auto-fail against certain effects.