Quick question

Not much. Paladins in D2 were far overpowered. They could do magic damage like mad, or physical and give aura boosts. (Dam hammerdins/smiters/zelodens/FoHers etc...) alone they were gods. The auras were almost only used with self interest, although they do help nearby people. Paragons however are very bad alone. They need a party. There DPS is not very high. About the only thing in common with paladins is that they can give boosts to nearby party members (or allies). The boosts that paragons give are almost always used for the party, not themselves. There are not many around though and the pve skills for them are very helpfull. in a big orginised party they are great. You know, just replace the word Paladin with Paragon in that paragraph and its mostly true. High physical damage? Spear has really nice DPS, and they have imba IAS. If you count in the fact that they don't have to run to their targets their weapon is on par with scythes in damage. Aura boosts? Shouts in Guild Wars are 10x better and can be stacked. The only thing that's not right is dealing magic damage.

Yeah Paladins could solo in D2, but EVERY class in D2 was meant to be able to tear the game apart solo, where every class in GW is meant to be part of a team, so its not much of a good comparison.

So is the Paragon kind of like a paladin in diablo2 ? just kind of a class with a lot of group buffs? The give godmode to the rest of the party and the party then buffs them to do mad damage. But I don't know if they are like D2 paladins.

Paragons do pathetic damage.
Yes, their auto attack is nice and they got good IAS. But in hard mode, nobody cares about auto attack. Paragons lack any significant armor ignoring damage source.
However, as physicals, they profit greatly from having skills like Barbs, Orders or Ebon Battle Standart of Honor around. Those, combined with Asuran Scan, give some great damage even in hard mode.
However, this damage is not coming from the Paragon himself but mainly from the other classes supporting him.

That's what makes Paragons great in groups: They get their damage from "outside" and can focus their skill bars on party support, giving the party a strong defense.
Especially in Paraways (groups of 8 Paragons) this concept is used very sucessfully.

However, a single Paragon in a group usually isn't that useful. Without the synergy from different shouts and chants (to trigger refrains or echos) the Paragon is rather weak.
Except for the Imbagon build, which is very popular for that reason: It's basially the only thing a single Paragon in a group can do. I would phrase it differently.
I would say paragons do very solid single target damage (their spear skills are pretty strong), that can be boosted by all the stuff you said, but aren't as good as other physical in damage department cause they lack multiple target and/or multiple attacks on same target.

Their strength though, comes from the fact that if you give them 2 spear attacks, aggressive refrain, there's nothing to fear, some sort of adrenal shout, you have 3 frees slots on a character that (at least) do solid single target damage (which by the way is quite good in some HM elite areas) and provide 30%+ damage mitigation of the time pegged with a 60 health heal party every 10 secs.

Additionally, they are quite sturdy and possess the resource engine to spam expensive stuff.

Considering physical teams with barbs, order of pain and EBSH are one of the most powerful out there, the paragon seems to fair good.

And that is without bringing [[Save yourselves] into this.

A good D2 Paladin could Solo the entire game. Paragons can't solo pretty much anything. Oooooh yea I remember doing Hell difficulty Baal runs with my insanely over powered Enigma owning Hammerdin.
If only my Paragon was that powerfull