Yeah totally agree but mostly this is a result of Zard trying to fill out the entire span with Best at S-Tier and Worst at D-Tier just because that's how Tier lists typically work.
Really it ought to be the latter of what you wrote above with Sorcerer at S-Tier, Wizard at A-Tier, and the worst classes as B-Tier, because in reality no classes are actually all that bad. Even the worst class (Ranger) is totally playable now and not really all that far behind the best class.
I think there's still room for classes to be C-tier. 5.5e has mostly addressed the D-tier issues, but there's still some....I guess I would call it +/- factors involved. IMO, Ranger has been lifted from D to C by 5.5e--it
passes.
Wizard is A+ if you have
either a GM who lets you pick up spells frequently, or (as noted) fewer encounters per day. The former definitely isn't guaranteed, but the latter is in my experience
almost universal. That is, I've literally never had a single 5e group where the group
actually did do 6-8 combat encounters per day. Maybe, MAYBE an average of 5 encounters per day. If you have both of these effects, Wizard is absolutely S-tier even at lower levels.
Conversely, if your group is starved for short rests, I could see Warlock, Fighter (especially Battle Master), and Barbarian becoming X- or even dropping a tier.
Certainly the tier ranges are much better than 3e's tiers were, but that's damning with faint praise given how
absolutely horrendous the balance problems and tier differences were in 5e. "Better than one of the most broken games ever published" is hardly a difficult bar to clear.