A new Unearthed Arcana appears! College of Eloquence and Oath of Heroism paladins

[LudicSavant]

Caps lock is to point out that, if multi-classing to 3 levels of champion is a reasonable option (not necessarily the best option, but a good one nonetheless), getting that for the cost of a bonus action is very good.

You say that almost like you're taking those 3 levels just for Improved Critical.

You get more than an expanded crit range (all day, with no action cost) from 3 levels in Champion. You also get +1 AC (fighting style), Second Wind, and Action Surge.

It's very good, better than all the channel divinities of the PHB oaths

Vow of Enmity not only improves your crit rate (having Advantage nearly doubles it, or triples with Elven Accuracy), it also makes you much more likely to hit. And it too is a bonus action.