I never played a Paladin in WoW. The biggest reason for this was that I played Horde at release, and was never big on creating alts. When TBC came out, I rolled a space goat shaman. Now that Classic is here, and my goal this time around is less about the end-game and more about just enjoying the trip, alts seem like a much more favorable thing. My main is a 32 human rogue, and my original alt was a gnome warlock to play alongside my wife’s gnome mage. However the pairing of two casters, both cloth wearers, isn’t ideal.
In comes the possibility of a paladin. There as been a lot said about how boring a paladin is to play, being that you auto-attack things instead of spamming skills like say a rogue. And this is true; at level 1 a paladin starts with a heal (Holy Light), and a 15 second buff that adds holy damage to your auto attack (Seal of Righteousness). That’s it. When you level up you get your first aura (Devotion Aura, an armor buff) and then finally at level 4 you get another buff (Blessing of Might) and Judgement, a spell that uses up your current Seal to do something. Using up Seal of Righteousness results in a short-ranged damage ability.
At level 4 here is how every combat plays out: Have seal running, use judgement to start the fight. Re-apply seal, auto-attacks. Mob dies. Every. Single. Time.
Now here is the thing; I don’t mind that. At all. Outside of PvP combat and maybe some boss/raid encounters, WoW isn’t an ‘action combat’ game. The slower pace allows for efficiency on when to use your abilities, rather than measuring who can hit the keys/mouse the fastest like in a FPS. Now yes, the Pali at low levels is taking that to the extreme, but again personally I don’t mind. Especially not for an alt as something else to play alongside a rogue. Perhaps by level 30 I might, but for now I enjoy the simplicity of mobs dying via autoattacks from a giant two-handed hammer to the face.
Hardcore Casual 
The pally starts rough. We were doing harvest watchers in a small group the other night with my pally and I realized while running off to pull my aggro radius had greater range than my judgement. But pallies get some interest stuff as they go along, plus you have a special epic mount that requires a quest. But for quite a while you’re stuck running up to mobs while almost every other class can pull from range.
My memory of this time may not be wholly reliable, but your level 4 experience there is basically the same all the way to 60. At some point you get Hammer of Wrath so you have something to do when the enemy is below 20% health. You also have some skills like Exorcism and Holy Wrath that are only usable on undead. Exorcism is notably the only ranged attack Paladins had back then, you’re stuck body pulling everything else. YMMV on whether this is really more boring than e.g. spamming sinister strike and eviscerating, though rogues at least had some stealth abilities and other finishers to make things a little more interesting.
Anyways Paladin combat is very simple, but then WoW combat is very simple. It’s basically two punching bags wailing on each other until one of them does more damage than the other has effective health. There’s no way to do anything like dodge, block, parry etc, as these are all percentage chances that lie entirely outside of the player’s control. WoW these days has more buttons to press and flashy spell effects, but the basics haven’t changed at all.
Looking at the skill list it does appear that Paladins get more ‘stuff’, including different offensive abilities, but then options don’t always translate into skills you actually use (the rogue has a ton of stuff I rarely use at 30).
There’s no way to do anything like dodge, block, parry etc, as these are all percentage chances that lie entirely outside of the player’s control. WoW these days has more buttons to press and flashy spell effects, but the basics haven’t changed at all.
Interrupts do make a very big difference, as does kiting with snares. There are also dispels, stuns, other cc, various movement abilities to close or disengage, and offensive/defensive cooldowns whose timing can determine the success or failure of a fight. It’s not the most complex combat system in gaming by a long shot, but to say that there is no interactivity beyond moving the hp bars is not accurate.
Classic Paladin is terribly passive solo, but it’s super-enjoyable in a dungeon group. Especially if you can be the “5th-man” and support both the tank and the healer. It’s designed around passive offense and active support.
Unfortunately, that role doesn’t scale past 5-man groups. Better to take an extra tank and healer rather than 2 support.
Way back in 2005/6, all I remember reading/hearing was how easy Alliance-side raiding was compared to Horde because they brought 4+ Paladins to buff/heal, and especially in longer fights, Paladins basically don’t run out of mana. (Also dwarf priest with their broken fear ward).
I get they aren’t a viable main tank in raids, but it sure sounded like they were always welcome in a raid group (especially compared to shamans for Horde).
Alliance-side raiding was easier mostly because a single Blessing, Blessing of Salvation, is overpowered.
Paladins become pure healers in raids. But it’s a very different playstyle than the ideal “5th-man” support style in dungeons. That change/disparity was a source of great unhappiness to paladins back in the day.
Here’s a post I wrote about the subject at the time: https://blessingofkings.blogspot.com/2005/12/paladins-in-raids-part-i.html