I dunno man. I mostly agree, I do, but not wholly. Cleric should be s tier aside from soloing. They are 90+% of the time the bottleneck for what you can get done or how much you can split raid, and in groups their complete heal is the only reasonable way to keep a charm pet consistently going; alternative tricks to heal pets seriously impede how well you can use said pets as tanks, as I think they all require out of combat gimmicks.
I actually agree, but when I started this I didn't even have S tier. The other people working on this wanted me to add S tier and F tier. I agreed to S tier, but F tier is a fucking waste since it's going to only be Rogues in soloing basically so what's the point. I think C tier conveys that. They also wanted S+ tier which I think is fucking redundant. I will admit I could've maybe, and still can, S-A-B-C-D-F, but in shit like classic so many classes end up as "not the best but not bad" that there's no really fleshed out caste of classes. Like druids in Classic raids aren't great, but are they better than Paladins? Yeah probably. But are they better than Warriors? Yeah maybe? It's very weird. And then there's all sorts of specialty shit like Paladins in Crypt of Decay soloing or druids quad kiting aviaks and like I've mentioned Shamans soloing Dragons. Yes they can do that thing, but put into any other situation outside of that specialty they're not nearly as good.
The rating at the bottom is pretty much the "S" tier ranking beyond the color coded graph. As you can see, clerics are always the best healer in every slot. It even lasts this way until maybe PoR or beyond when you might want a druid/shaman for their aura/epic click over a cleric for simple grouping. I will admit after thinking about it, I think you COULD, possibly, do raids without clerics up until Velious if you had enough druids. It'd be pretty hard, but I think you could. Once you hit Vulaek and AoW type fights you need the efficiency of a CH rotation or you're boned. Even with 20 druids there's just no way their shit "big" heals would be enough for AoW spikes.
That said in the grand, grand scheme of thing. Enchanters, Clerics, and Warriors(beyond classic) are S tier picks for raids and only warriors fall off in group content, but they come back MUCH stronger in SoF+ expansions. I just wanted to use a single S-tier classification to point out the importance of these certain classes in their scenarios.
-Enchanter is still, in my mind, just the fucking most important tool for a raid via clarity/haste/CC/ and charm pets. Bards can do some of that but they sure as fuck aren't keeping Xegony packs or Rathe Council mez locked. But the problem with enchanters is their actual raid dps is locked mostly to their charm pets. If you don't have access to good charm pets, you start hitting saturation after about 4 enchanters in most raids. If there's plenty of pets the more the better if they know how to control them and you're not fighting a dispeller.
-Clerics always good. CH is king whether it's for long fights up until GoD where the rotation falls off, or just to top off charm pets with massive 32khp health pools. They're the only source of AE heals for quite a while and shit like NToV they're crucial. In groups they're very nice, but honestly a druid/shaman combo offers more if the druid is willing to be main healer than a cleric as you'll probably have a shaman as well. And as your raid gear scales in a lot of group content there's not much for the cleric to do outside of healing charm pets. Clerics have a much higher saturation point depending on expac, but you CAN have too many clerics if you have enough good ones. At that point they offer nothing but being able to rez/rebuff the dead because their damage is pitiful outside some undead fights where unless they crit Turn Undead they still won't break top 10.
-Warriors suck in classic. They've got no defensive, and their threat is 80% tied to procs. Once Kunark comes out they not only get some decent 14/24 epics, but they get the big D, Defensive discipline. This fucking thing is the crux upon which all boss tanking will be built on from now to forever. If you don't have a warrior/enough warriors, outside of glyph blasting, you are not raiding. Bosses hit so fucking hard later on unless you're in a 12 cleric raid situation, it ain't happening with an SK/Pally. We had a few SK/Pally tank AoW at the end of Velious and some even survive, but it was rough. And that was with geared clerics and geared dps as well. Warriors get really good dmg/delay weapons and around Luclin they CAN do very respectable damage in groups where you don't feel like they're a waste. But again, they're mandatory for future raids. There's no way around them. Entire guilds have crumbled due to losing "the geared warrior" or "the good warrior". They are crucial. That's why a Kunark start is great because they come with Defensive at the ready and they don't have to suffer through being plate rangers for 3 months.
So if I were to add more than one S-tier to classes, yeah, Cleric and Warriors are definitely S-Tier for Raids. I think they're the least valuable in Clasic raiding, but their stock just goes up as expansions progress.