The 5e Ranger had a very weak spell list across the first 3 levels of spells, with some good spells that come online late game. The Paladin list, in comparison, is much stronger, and the Paladin is one of the best-built classes in the game. Part of the issue is the Paladin's better damage mitigation (saves, Lay on Hands, aura, higher AC) vs. the ranger's lack of defensive features on most subclasses, but the other part is the lower-utility spell list.
I would cut Hunter's Mark entirely, as it takes up far too much BA space (vs. Swift Quiver, TWF, commanding a beast companion, and various other class features) and just give them +WIS to damage vs. favored enemies.
Looking at things on the Paladin list that are missing from the Ranger list in terms of capabilities:
Deadly strike: 1st level, free action. Expend a spell slot to gain 2d10 bonus damage on an attack against a Favored Enemy. It's like Smite Evil but more limited in who you can use it against, so the damage is slightly higher. Doesn't tie up concentration or become weapon-limited like Branding Smite or the Entangling Arrow one.
Lightfooted Travel: 2nd level, 15' radius. The caster and up to 6 allies of his choice who stay within 15' have their overland travel speed double as long as they focus on traveling and not combat, for up to 4 hours per day.
Rangers are meant to be great at cross-country travel, but a Paladin with 2nd level spells is faster and better. So is a level 6 Totem barb with the Elk Totem (increased overland speed for the party). Longstrider doesn't cut it in comparison.
Natural Shield: 2rd? level, Concentration up to 1 minute. Trees, boulders, vines, walls, and other surroundings seem to always be perfectly placed to foul attacks against the caster, giving him 3/4ths cover against all attacks.
+5 to AC for 1 minute and a bonus on Dex saves should help with damage prevention, while staying on theme with the ranger as being a nature-y fighter.