Is that really a problem? Someone who needs a "simple" class probably isn't going to notice a slight performance shortfall.
It sort of is. Consider that D&D is a co-op game, and everyone needs to do their part in order to achieve success in adventuring. If you have a party of four, and three guys are say, B-Tier, and one guy is a C-Tier, you might struggle as a group. And even if not, I'm sure eventually the C player is going to notice something weird is going on.
Take my current group. We have a Cleric with cursed luck (it really is, I've been starting to log his rolls to see exactly how much more he struggles than we do. And despite having the highest AC in the party, and the DM rolling openly, he gets hit a lot more than you'd expect, something else I'm compiling data on), a newbie Dex-Ranger who has been forced to dual-wield daggers since we haven't found magic short swords for him, a Bard who usually shows up well-medicated due to IRL medical issues (we really thought we were going to lose him) and generally either picks spells completely at random or tries to melee with a rapier, a Monk 5/Fighter 1/Rogue 1 (I have no idea what he's doing, but he's one of the most competent players we have), and my Wizard.
I hardly ever use raw damage spells, preferring to use mostly crowd control or just cantrips (and I'm super stingy with my spell slots to boot, having learned how to spell sling back in AD&D). I don't have a 20 Int, and I actually took the Healer Feat, lol.
And yet, last session, after I managed to completely lock down an enemy caster and defang her goons, he kind of looked at me and was like "I went down twice in this combat and I think your Wizard is the only reason I'm still alive. Why am I even here again?".
I take no pleasure from this- sure, I want to do my part, but I don't want to make other players feel insignificant. His class should give him superior damage and survivability over mine, and he's even a half caster on top of it. But because he chose a fighting style that really plateaus, has made some dubious spell choices, doesn't have the ideal weapons for his role, and has a terrible subclass, he's struggling and really shouldn't be.
Now all of his issues are correctible, he simply hadn't asked yet, and somehow when I make suggestions, people think I'm telling them how to play their character (so I don't make them unsolicited as a rule). But I think it really speaks to how one class or subclass shouldn't be worse than another. Honestly, I'd make a simple warrior class do the best damage, since that'd be really all they could do, since they're likely sacrificing versatility!