Asisreo
Patron Badass
Thinking back on your question, I actually think a ranger subclass with only a limited list of selectable spells may not only be balanced, but OP depending on the spell chosen. In fact, I'll actually play along with the "no 5th-level spell" thing going on.So you WOULD pick a ranger subclass that just gives you druidcraft and four Druid spells from a very limit list?
Options are power. Getting blight as your fifteenth level class power is balanced then, right?
Of course, you arbitrarily chose a specific Druid cantrip and 4 druid spells either because the spell list of a Ranger is close to a druid or that the elemonk's spells sometimes align with a druid's, but there's nothing saying they must. These points would contradict themselves anyways, since if it was because it was the druid spell list is similar to a ranger's, a monk has no spell list to derive from. If it was because the elemonk's spell list resemble a druid's, they also resemble a wizard's or a sorcerer's.
Anyways, I've made a list of spells which could potentially make this theoretical Ranger subclass almost overpowered. I'm structuring it similarly to the monk's disciplines.
Supernatural skill: Can cast Guidance at-will
Mark of the wild: cast Hex using a Ranger spellslot
Curse of the Forest: cast Bane using a Ranger spellslot
Quick Aid: Cast Healing Word as a Bonus Action using a Ranger spellslot
Mystical Force: as an action, force a hostile creature to make a dexterity saving throw using a ranger spellslot. If they fail, they take 4d6 piercing damage and are paralyzed until the end of their next turn. If they succeed, they take half damage and are not paralyzed. You can upcast this for an additional 1d6 damage.
Nature Raid: As an action, force a hostile creature to make a constitution saving throw. If they fail, they are paralyzed until the end of their next turn. If they succeed, they take half damage and are not paralyzed. You can upcast this for an additional 1d6 damage.
Imbued strikes: your arrows have been imbued with the power of nature. When you take the attack action, you can use a ranger spellslot to make your attack quicker and more magical. your attacks are magical for this turn and you can make an extra attack as a bonus action this turn or 2 extra attacks if you are duel-wielding.
Call upon nature: as an action, while spending a ranger spellslot, you can move either the earth or plants as you see fit. Choose an area of earth no larger than 30ft in any dimension and move it so that in any way except it cannot harm or trap a creature. If you choose a plant, you can move it within 60 feet of its original position. The plant must be Huge or smaller.
Aspect of the animal (6th level): you can cast enhance ability.
Claim mount(6th level): you can cast Find Steed
Nature's beckon(11th level): you can cast revivify
Cheetah's Fury(11th): you can cast Haste
Return to the Natural(11th): you can cast dispel magic
Bestial Roar(11th): You can cast fear
Beast Form(15th): polymorph
Conquer Nature (15th): Dominate Beast
All else equal to how the Monk operates, I'd say this is a decent list of features to choose from.