I like the idea of fourth level spells being long and costly activities that are a serious undertaking for the mage that takes them. I'm not familiar with the UA rules but I'd be interested to see it.

Possible appropriate core spells might be:

Break Enchantment
Bestow Curse
Reincarnate
Scrying
Control Water
Dismissal
Divination
Discern Lies
Dispel Magic
Secure Shelter
Minor Creation
Arcane Eye
Detect Scrying
Lesser Geas
Illusory Wall
Hallucinatory Terrain
Stone Shape
Tongues
Neutralise Poison
Imbue with Spell-Like Ability
Sending
Command Plants
Armour of Darkness
Dominate Person
Tree Stride
Modify Memory
Mnemonic Enhancer

Maybe in a dedicated healer archetype, even Raise Dead.

Generally I'd expect these to be limited to 1/week instead.

Since everyone seems happy with the Poet, I'll be going over them next.