Lets see. First off, cool stuff. Second off, some thoughts.
And sorry in advance, I'm calling them skill trees, not trait trees
I think you need to expand the skill trees for rulers, warlords, and casters. Right now a ruler starts the game with 2 skills maxed and another at basic. That's a 40% income boost and a 40% upkeep reduction on top of some other small bonus. Now, having a bonus like that might not be a big deal (I mean, it kinda is, but everyone can get it), but it doesn't really leave any room for growth in your ruler. You have a similar problem with casters and warlords, but it is lessened by the fact that you'll want to get stuff like hardiness for your warlords and multiple schools of magic for your casters.
Okay, on to suggestions.
Findamancy - Something similar to Lookamancy, but much cheaper, and instead of getting to see the squares you try and find a particular type of unit (Siege for example) in the area, and get a yes/no hit on if it is there. Multiple casts might let you narrow down the location, but wouldn't tell you the type or side or anything (though would provide a good combo with a lookamancer)
Predictamancy - At a cost of 5/4/3/2 per attack, a Predictamancer may allow the attack to be rerolled. The reroll can itself be rerolled.
Mathamancy - Superior information on potential unit matchups give a side .1/.25/.4/.5% bonus to attack and defense per juice spent
Turnamancy - I think you need to put the thinkamancy dominate here. Produce 1/1.3/1.6/2 pop points per juice, only usable in cities. Master Turnamancer only spell, requires 100 juice to cast, and costs 300 juice, potentially draining into future turns to make a side skip their turn. They produce revenue, pop things, and require upkeep, but cannot move units, attack, or change build orders.
Dollomancy - Able to create artifacts for units to increase various stats or grant special abilities such as flight. Cost varies. All items are permanent, but may have limited uses. May heal cloth golems as a healomancer heals other units.
Weirdomancy - Able to increase a units movement at a cost of 10/9/7/5 juice per point increased. Able to allow one unit to ignore the wall bonus of a city at the same cost. Able to remove a special, or add one (such as flying) for a turn at a cost of ... I don't know... 20/17/13/10. Able to create a portal. Portals are two way and each portal can only link to one other portal. Each portal must be made individually, and the caster must be present to create each portal. Each portal costs 200 juice, which may be spent over multiple turns.
Dirtamancy - Able to reduce the cost of upgrading or building a city or city improvements by 1/1.3/1.6/2% per juice spent (maximum 50% reduction). May create and heal crap/mud/dirt/rock golems as per a dollomancer. May create up to 20/40/70/100 juice worth of traps in a hex which deal 1/1.3/1.6/2 hit per juice to any enemy stack entering the hex. Dirtamancer may activate/deactivate the traps at will as long as they are within the hex. Active traps always spring on the first stack from another side that enters them.
Changeamancy - Can turn a unit into another unit. Costs 1 juice per 1/1.3/1.6/2 pop points difference between the two units.
Dittomancy - I think you've got this fairly well covered.
Lookamancy - A bit more clarification on the foolamancy/lookamancy interaction would be nice, but otherwise looks fine. Might want to include an additional cost based on distance (so closer hexes are cheaper to prevent people spying enemy capitals with impunity)
Thinkamancy - Change the dominate to a temporary effect that lasts one turn. May link to another caster, allowing them to share a pool of juice, in addition to reducing juice costs by 5/10/15/20%. May create a three caster link, creating a combined pool between all three casters, allowing access to more awesome spells. Breaking the link has a 50/40/30/10% chance to kill each caster involved in the link.
Foolamancy - As per veil, may also make a stack look as though it contains double the number of units.
Flower Power - May poison a unit at a cost of 1 juice per 1/1.3/1.6/2 hits of the unit. The unit dies at the end of its turn. 100 juice, may prevent all combat in a hex for a turn.
Signamancy - I like it.
Date-a-mancy - Good stuff
Shockamancy - Deal 1/1.3/1.6/2 hits per juice as an attack.
Croakamancy - Sounds good.
Retconjuration - Very interesting, I like it.
Hat Magic - Create a pair of linked hats for 20 juice (can be spent over multiple turns), which may then send items (such as those created by a dollamancer) between the two hats. Pull a unit (must be non-sentient) out of a hat for 5/4/3/2 juice per hit of the unit.
Carnymancy - May add or subtract 1 from any die roll at the cost of 5/4/3/2 juice. May only be used once per roll. Must be reused on rerolls generated by predictamancy.
Rhyme-o-Mancy - Increases the move speed of a stack by 1 per 20/17/14/10 juice spent. Increases the effective juice spent by another caster by 1/1.3/1.6/2% per juice spent.
Luckamancy - Looks good
Healomancy - Not much to say here.
Moneymancy - Dittomancer says "Not much to say here, can't say much here."
Whew, so, that was quite an exercise. Feel free to change the points costs on stuff, because I just pulled them out of thin air for the most part.