The vanilla/classic paladin has only one viable role in PvE, healing or Holy spec. Here is why:
Retribution
- No threat reduction in PvE. Take some decent gear and a good 2-hander into Molten Core and attack a Lava Giant that is being tanked and you will see what I am talking about. Other viable dps specs have some threat reduction. Holy damage is the highest threat damage in the game.
- Good burst dps, poor sustained DPS. No damage over time, bleeds etc.
- No melee strikes. No controllable dps. Essentially no controllable dps and no dps rotation. DPS is auto-attack. Seals are just weapon buffs. Judgement is not that effective in PvE.
Protection
- No taunt. Paladins are unable to taunt off another tank or swap aggro with another tank.
- No tanking gear for Paladins in end game. The only tanking set for paladins is level 57 and there is nothing at level 60.
Paladins were deliberately gimped by the devs about 6 months before vanilla release.
Paladins are cleric healbots in vanilla classic end game. Flash of Light, Holy Light, blease, cleanse, maybe judgment. That is it. This is unlikely to ever change. If you want viable Paladin dps and tanking in pve, you will have to wait until BC classic to be re-released.