Honest question to ETA Hoffman and whoever else would like to answer.
Do you find Dreamer to be noticeably better than Lilith, Jacob, Collodi, etc?
I agree that he's a powerful master and summoning is a big part of his power but I often feel like other masters are as viable or sometimes more viable picks depending on the schemes and strategies. If you are spending 5ss for the summoning upgrade, 4-6ss for mobility from daydreams, additional soulstones or daydreams for the required suits to cast his spells and 3 9+ cards per turn you are committing ~20% of your soulstone resources and in most cases the top end of your hand every turn. I think the trade off is worth it in many cases but in many cases I'd much rather have a stacked hand from lilith + primordial with less activations than a depleted hand with the dreamer.
I don't feel that the mr. Tannen interactions with Dreamer are particularly strong although they are decent. I tend to take tannen when I want him for his cooler and chatty abilities, otherwise not.
The other thing I have not seen mentioned so I thought I would throw it out there: Does anyone else feel that a lot of the nightmares basically pay a summoning tax? Meaning they are not good enough stat and ability-wise for their soulstone cost because of the fact they can be summoned? What I notice is that when I'm playing a game with a synergy independent master like pandora, zoraida or lilith there are quite a few nightmares that I will basically never hire.
Compare alps to marionettes. I will hire 3-4 marionettes almost every time I play Collodi. I will sometimes summon but never hire alps when playing the Dreamer.
Compare lelu and lilitu to beckoners, coryphee, illuminated, black blood shaman, doppleganger etc. I think lelu and lilitu are good to summon with the Dreamer because they heal so fast but I don't hire them (occasionally I'll hire a lilitu on her own)
Coppelius, I have no idea why people rate coppelius so highly. I hear people talking about how he's good on offense? Without focusing he does weak damage 1 and for the same price as someone who is as card dependent for triggers as coppelius is (after Summoning dreamer has crushed your hand) you can take baby kade with depression for the same price, who only needs a throwaway low crow. Kade is legitimately good on offense. I can see coppelius as sort of a glorified insidious madness for running schemes while beating up on other scheme runners a bit. He also really suffers from being summoned in at low health because he doesn't heal quickly and getting eyeballs with df 4 and low wounds before being deleted off the board is not easy.
Stitched are solid 6ss models. They have some very nice synergy with the dreamer by healing above hard to wound and some anti-synergy as well by the opponent being able to use their card advantage to turn gamble your life attempts back on the stitched. Outside of Dreamer and sometimes Collodi I don't tend to hire these.
Insidious madness I like summoning with the dreamer and hiring with pandora because of the wp synergy. These feel about right for a 5ss wp centric objective runner.
I think daydreams, weaver widow and teddy are all solid models in their own right and well worth the price of hiring. I use both weaver widow and teddy in many neverborn crews and would use daydreams in other neverborn crews (PANDORA!!!) if I could.
I guess to summarize my position: I find summoner dreamer good, right up there with but not really better than: Lilith, Collodi, Jacob and Pandora. I find him more versatile than Jacob and Pandora, about as versatile as Collodi (grrrr reckoning!) and less versatile than Lilith, who seems to be good at everything.
If dreamer's summoning is overpowered I don't think it's because of the strength of his nightmares. I find many of the nightmares to be sub-par for their cost and only see the light of day because of summoning and niche hiring.