The mere fact that you mention paladins and bears among tanks in vanilla is enough to dismiss all your other reasoning.
The mere fact that you think you're actually stating "a fact" proves that you're only aware of vanilla mechanics via osmosis and word-of-mouth. Bears and paladins are just as able to tank as warriors are. Non-raid content, that is. The two reasons why paladins tanks weren't a big thing in vanilla raiding were that they didn't have taunt and their reliance on mana. Some bosses were untauntable anyway and with a good raid, boss fights were short enough, so a pally could tank certain encounters as well as a warrior. Not to mention that they were the absolutely best AoE tanks already, and some guilds (like mine) used a pally tank to do all pack-tanking in MC and BWL, who could then replace tanking gear with healing gear at other times. The only problem that bears had in vanilla was that since they did not have block, they could not push crushing attacks off the hit table. But their higher achievable armour rating and higher HP pool meant that they were superior over warriors when tanking magic dmg bosses whose attacks couldn't be shield blocked away - not to mention that once you got into Naxx, you needed EIGHT tanks for the four horsemen and hardly any guild had eight well-geared warriors at hand.
Tanking as a druid in vanilla days was pointless and we needed huge amount of gear which was only avaible after Zul'gurup and AQ 20 drops. Not worth the hastle.
Nonsense. With MC, BWL and crafting stuff, you could get a good enough tanking set together before ZG and AQ20. The items from those instances made FERAL CAT druid gameplay viable again, in that the items made feral cat druids somewhat comparable to rogues.
Whats equally retarded is the claim that all specs were feasible. Ret Paladin? Shadow Priests? Warlocks? Fire mage in MC?
You might need to read a dictionary to understand the difference between feasible and optimal. Yes, 1 shadow priest in Molten Core, in the warlock group, can increase the overall raid DPS more than replacing him/her with yet another warlock or mage. Also, after the warlock talents were revamped (I don't remember which patch it was) they were DPS kings alongside mages if not even better. Ret pally dps sure was pitiful, but he could heal and tank at the same time as do little melee DPS. The fact that min/maxer-guilds, who sought out the optimal composition, didn't use them does not mean they weren't feasible.
Yeah, the gap was more immense than people realize. Some specs were literally useless (ret pala, enh/ele shaman and a lot more) for raids, but people took them to fill slots.
You and rashiakas are either misremembering, were playing on a shitty server, or you are thinking of some buggy private-server. Well-geared elemental shaman rivals mages and warlocks in dps, problem is sustaining that damage over a long period. If she gets Innervation from a druid, in addition to popping major mana pots, they can keep going well enough. Enh shammy has it worse but you could always swing Nigthfall and keep the debuff up, justify your existence that way, same with ret pala - plus everybody likes more totems/blessings.
At about level 40, there was a clear problem that you just couldn't find any more quests for your level if you played in a party. You had to grind instances till level 44 at least.
There definitely was a lack of XP if you played in party. And even without party, there was a "gap" at level 40, which ruined my first character. I skipped some quests, played in party a lot and then had to do quests of higher and higher level until I couldn't do anything anymore with my character and got stuck at level 42 I think.
That aspect could've been done somewhat better.
Wrong. You do not need to grind at all to reach level 60. You just need to scout out multiple zones and you need to do dungeon/elite quests as well. I did it on vanilla, I did it with two draenei characters before patch 2.3 nerfed the old world, I've done it on private servers with 1x rates as well. You get more than enough XP from quests.