Probably shaman as it is the only one not compatible with vanilla humans.

It was more of the XP penalty (at least on Blue) as to why hybrids were shat upon. Rangers being the worst tank hybrid were especially shunned.

People love Rangers on Green, and it seems like the Ranger epic is getting completed regularly because ever FKing Ranger has it .

Rangers were one of the most popular classes in 1999 (Paladin quite popular too), thanks to the inherent fantasy-genre fanbase and because of being nearly identical to Warriors in terms of melee capability, while having some useful spells and tracking on top of it. The hybrid exp penalty was also not really known at the time.

When Kunark came out they quickly went down the drain in reputation, because their melee capability (especially tanking) got a lot worse and they didn't gain anything special to compensate for it, and the hybrid exp penalty became more known to the playerbase. Their lacking melee capability was compounded by dual-wielding generating more aggro than 2-hand melee, and lots of people didn't understand how to use Root for proximity aggro, so Rangers were taking aggro despite doing less damage and then not being able to tank too well.

Also the first player to hit Level 60 was a Ranger (achieved by camping NPC's in South Qeynos) and went on the message boards talking about how weak the class was at that point.

Yeah, back in the actual early days of EQ, ranger was actually considered overpowered because they could "do so many things." This was before anyone had any real notions of who was the best tank, the best DPS, etc. Ranger and druid were considered the OP classes because they weren't limited to a select few things they could do. At the time, any class with dual wield and double attack (or a pet that had it) was considered top-tier DPS, and any class with taunt was a tank. Having snare, root, harmony, nukes, dots, sow etc. on top made it seem OP.

Then people realized that being able to do a bit of everything wasn't quite as impressive as it first seemed. Still, during the phase of a fresh server where everyone's just wearing banded anyway (or Lustrous Russet!), ranger is the best non-raid tank since they have the same shitty armor as anyone else, higher defensive skills than knights, and snap aggro. It's not as if it's really efficient to use CH in classic content anyway, so the ranger's slightly lower HP pool doesn't matter in any content that anyone would permit a ranger to tank in the first place.

Split among 5 or 6 people it's not that big of a deal, and one would think the utility a half-decent Bard brings to a group is worth the penalty.