Quote Originally Posted by veti View Post
One: paladin should not be a base class. It's a prestige class, available by invitation only to people who, in the eyes of some competent authority, have proved themselves worthy to take it. This means that the PC has to go through an extended "audition" before they get the funky powers, immunities and whatnot. It would dramatically improve the chances that the PC and DM are on the same page as to how the paladin is supposed to behave.
As an aside, the decision not to move Paladin to the "prestige classes" is exactly where the whole idea of "prestige class" changed from a great idea to munchkin fodder.

Quote Originally Posted by kyoryu View Post
I do find it somewhat interesting that this is never called "The Assassin Problem".
Evil parties (or even just evil characters in non-evil parties) have enough problems of their own. Also even where assassins lose their powers if they ever become non-evil (2e and before?), they could budge with a single good act as a compromise. Of course, if you have somebody playing an assassin because the can typically pull off a "death attack" on other members of the party your problem player isn't going to be fixed by not playing an assassin. Problem paladin players typically can't pull off "the paladin problem" while playing clerics. "The Paladin Problem" is closely tied with the "DMPC Problem" in that it takes agency away from the rest of the players. Once the assassin likewise removes agency (presumably by killing their characters) of other players, you have a similar problem.

As mentioned, the problem with the paladin lies in the code of conduct. It is far too narrow. The problem comes down to giving the [problem] player [or DM] too many chances to twist a certain option [for the entire party] as the only one allowed by the code. Basically, every major (and sometimes minor) choice comes down to an alignment debate. Use the 5e oaths and the ability to manipulate the party/player [for bad players/DMs] is limited to plot-centric railroading.
You can't have one player [or DM] determining the agency of the entire party. On the other hand, the 5e oaths are a pretty good reason to tell the party "you aren't allowed to ignore the adventure hook I spent hours preparing. Now get in the dungeon already."