Well, I really like the Holy Trinity of the Paladin specs: Tank, DPS, and Support/Healer.
As the RPG Paladin (DnD for example), you can play in whatever role that is needed, for me it's just fine for a Paladin.
One only different spec that pops in my mind at the moment is maybe a caster DPS, using holy spells, but I believe that should be more a spec for a Priest. I don't like the idea of a Paladin stealing the thunder of a Priest as a Holy Caster DPS.
Could be a nice concept of a melee warrior with light and dark abilities, depending on the god he prays. The experience I have had with paladins are a religious static warrior with lower mobility than the warrior class, but with some ranged abilities to pull the enemy to himself. I think the paladin should be a warrior with two mana resources (faith and wrath), that way the most destructive abilities use wrath and the most constructive abilities use faith (making the difference between good and evil).
For specializations I think paladin should have a DPS specialization, a tank specialization and a support or buffer specialization.
Personally, i'd like to play a paladin like some kind of chaplain/warrior priest from warhammer, focusing on blessing and inspiring his allies with various buffs (e.g: "for the next 5s you pray for your ally and grant him 30% more speed" or "You inspire an ally and the next attack he makes will be 100% crit chance") also this spec could do an okayish damage to differentiate from healers.
Could be a nice concept of a melee warrior with light and dark abilities, depending on the god he prays. The experience I have had with paladins are a religious static warrior with lower mobility than the warrior class, but with some ranged abilities to pull the enemy to himself. I think the paladin should be a warrior with two mana resources (faith and wrath), that way the most destructive abilities use wrath and the most constructive abilities use faith (making the difference between good and evil).
For specializations I think paladin should have a DPS specialization, a tank specialization and a support or buffer specialization.
I think at least one spec should be like wow shaman enhancement combat style. With a vast variety of skills and resources, but to balance his versatility would be great to see him using two types of mana resources.