I used to think class system was inferior. I thought it was stupid, for example, that a person couldn't be good at using swords just because s/he wasn't a cleric.
Then I played some RPGs, including cRPGs, without classes. They're more complicated, and the end result is that you have to really know the system to advance smart. It's like the discussion about 3.5e versus 5e. 3.5e is versatile and if you know the feat trees well, man you can create some interesting characters who are really powerful. But the issue is that you REALLY need to know your stuff. If you don't, you wind up lost and confused and picking feats or skills that really won't help your character or party, and in the end you're replaying the game from scratch because after 3/4ths the way through you realized you didn't level up smart because you didn't understand the system like you do now. But now it's too late because you can't beat the game with your current level up choices.
This was Final Fantasy 8 for me - the first one that popped in my brain but certainly not the only one. I had no idea what I was doing for level ups, so I just picked stuff. Got to the part where you are about to face final chapter(s) and got stuck because my level ups were useless and not thought through well.
With a class system like 5e, however, it guides you more. It makes it so you don't have to be an expert on the rules or level up options to successfully build your character. It lets you focus on the overall picture and story of your character. "I want to be a rogue," as opposed to, "I want to be a...um...rogue with longsword proficiency that can also...um...shoot a bow...um...wait I also have to pick what in order to shoot well?... A feat called Precise shot? I need Point Blank Shot first? But I want my character to be good at shooting now. That sucks. If I'd known that I'd have picked Point Blank at character creation. Wait. Did you say my character sucks at longsword? Why? I didn't build up my Strength and I didn't take Weapon Focus feat OR Longsword proficiency? What feat/ability do I need to make it so I can fight well with a longsword? Wait! I can't take that now for a few more levels?"
