You say this now, but Spell Queller makes Reflector Mage look fair.
Do you have a list of what you're working with? I'm playing around with it a bit myself ( Standard ), but I haven't really gone into deck-building before ( am now trying to build this and B/R Vampires for standard. any good place to test? ). This is what I came up with so far,
would love to have some feedback from anyone as I'm not real experienced in deck-building;
1x Anafenza, Kin-Tree Spirit
Not vital to the deck, but is occasionally especially useful when you get to Bolster your Mausoleum Wanderer. Might be too cute, don't really know yet. Feel like this as a one-off is harmless.
2x Elder Deep-Fiend
Emerge from Reflector Mage. Seems like a good bigger threat for this deck.
4x Mausoleum Wanderer
Duh.
2x Nebelgast Herald
I haven't tested this but feel like this could be a decent addition. Do not know what amount would be right to run here. Maybe none? Maybe more? Multiple on the board will tap a lot.
4x Rattlechains
Duh.
4x Reflector Mage
Not a spirit, but that don't matter much.
2x Selfless Soul
I feel like two is the right number for now with the type of removal running around. Four might be too much.
4x Spell Queller
Duh.
4x Essence Flux
I thought Essence Flux might be too cute at first, but I feel like it just does so much; Upgrade Mausoleum Wanderer by flickering itself or any other spirit, re-use Reflector Mage, re-use Spell Queller in case they cast a spell that is a bigger threat than the one exiled, maybe even just to untap and buff one of your creature to block. Seems very versatile for just a single U in this deck.
1x Ojutai's Command
This seems great and versatile ( returning Selfless Spirit / Mausoleum Wanderer / Rattlechains in reaction to something, basically adding "Creatures you control gain indestructible until end of turn", Force Spike, and "Target Spirit gains Hexproof until end of turn" as modes ) but I'm not sure you want the full playset or even three.
4x Unsubstantiate
Slow them down. Bounce their big threat, Spell Queller it next turn. Remove a blocker for that final bit of damage. In some rarer cases, save your own creature / re-cycle ETB effects. If you have enough mana, you can be cute with Spell Queller and bounce it back while it's ETB is still on the stack.
4x Declaration in Stone
Removal, ho!
2x Always Watching
+1/+1 and Vigilance? Why not? Don't like a full playset here. Might not even be needed.
8x Island
6x Plains
4x Port Town
4x Prairie Stream
I don't really like how they're going to focus on the Gatewatch from now on with all sets. Though it would be great if Kaladesh's story just starts off with several stories of them just going around the inventor's fair and interacting with eachother without any instant conflict or threat. >w>