The Divine Sense feature of the Paladins looks underwhelming to me. It has limited uses, takes an action to use, and
- you know the location and type of any celestial/fiend/undead within 60ft, not behind total cover
- you detect any place/object that has been consecrated/desecrated within same area
Divine Sense gets blocked by a window, basically detects hallow but not any of its features, or even whether it's consecrated or desecrated, and does not detect possessions. On the plus side, you can find invisible imps?
My problem with this feature is that it seems to be close to useless. Unless you decide to randomly use it because your spidey-sense told you about invisible monsters or hallowed grounds, you can only use it to learn types of enemies you're already on the same room as. But because it takes your action to do so so, you probably won't this if you're already in combat.
Compare this with other class features at level 1. Barbarian get Rage, Bard gets Inspiration, Clerics, Sorcerers and Warlocks get a subclass feature, Fighter gets a Fighting Style and 2nd Wind, Monk get Martial Arts, Rangers get Favored Enemy, Rogues Sneak Attack, and a few get Spellcasting. Paladins get Lay on Hands (great ability), and Divine Sense.
TL;DR: Divine Sense looks very niche, has limited uses, costs an action, and doesn't seem to provide useful rewards. What am I missing?