0 - unplayable in 40 card singleton
1 - effectively unplayable
2 - has low tier constructed decks it might go in
3 - has mid tier constructed decks it does go in
4 - pretty powerful stuff with several potential homes, able to perform well in lower powered cubes
5 - powerful stuff that is either just too narrow or has too many superior alternatives
6 - fringe cube worthy
7 - cube worthy
8 - cube staple
9 - unpowered cube bomb
10 - powered cube bomb
Takenuma, Abandoned Mire 4
Just as free of an inclusion as the other legendary channel lands but a rather less useful effect. It isn't really interactive and is just a very low tempo way of getting action instead of a land. Castle Lochthwain seems significantly more exciting than this and even that was a bit slow for cube.
Weaver of Harmony 3
Too narrow for drafting cubes but quite the house in enchantment creature decks and quite the reason to build such an archetype.
Spirit-Sister's Call 2
A bit like a Recurring Nightmare which cannot loop things but doesn't have an ongoing cost nor a restriction to just dorks. All told this is way too narrow and slow for cube but it is powerful and likely to do some good things in places like EDH.
March of Wretched Sorrow 5
I'm stumped on this one. It is too slow without the cost reduction but it is too costly with it. You don't want to be going two for one to kill something with 2 toughness! None of the modes you can play this in are good by themselves but perhaps the flexibility of the spell is enough to push it over the line. Absolutely one for testing, if I were forced to guess I would come down on the side of not good enough but we shall have to wait and see. The ability to turn black cards in hand into two life a pop is pretty handy when considering things like Necropotence.
Light-Paws, Emperor's Voice 2
A kind of bad Kor Spiritdancer but still good enough to play in most singleton aura decks. Far too narrow for anything other than aura decks of course.
Oni-Cult Anvil 2
Cute way to turn the likes of Baubles and Chromatic Stars into extra value and a nice pairing with Daretti, Ingenious Iconoclast but the power here is pretty low as far as playable cards go and on top of that it is also rather narrow.
Okiba Reckoner Raid // Nezumi Road Captain 5
I think this card rather perfectly frames the issue with these saga flip dorks. Compared to most one drop beaters this is nuts, except that it isn't because it is never a 2/2 beater on turn one. First attack is on turn four by which point any crappy 2/1 can have dealt twice as much damage. Mild evasion helps keep this relevant longer than otherwise but it is still a low impact card. In a world with high aggression black decks this has a shot but for general use it just seems to slow.
Cloudsteel Kirin 1
Lol. This will win some games but mostly it is a below par dork with a risky low tempo desperation mode. There are better ways to avoid losing that don't involve crossing your fingers and hoping one of a a number of your cards don't get answered while you waste your mana and play weak cards.
Reckoner Bankbuster 7
A more beaty take on Mazemind Tome. You get three cards for seven effective mana split into nice convenient chunks of two. You also get access to a 4/4 vehicle as well as ultimately getting a good crew for the job. A slow card but playable and versatile. Cube is the kind of setting where this style of card works out very well. It stands alone well and does a selection of useful stuff. Not broken but impressively playable.
Sky-Blessed Samurai 2
In an enchantment based aggro deck sure, this is a cheap fat flier that both adds to and benefits from enchantment theming. Narrow but certainly with potential.
Nashi, Moon Sage's Scion 6
Versatile and somewhat scary card. It is quite like a Fallen Shinobi but a whole lot less narrow. Sadly this is a bit too fragile to impress all that much. If you try and play this for 1BB it is getting blocked or killed all day making it a bad card on the whole. When playing it for ninjutsu the cost is greater as well as requiring more setup. Then you are relying on hitting something good to cheat on mana with. Hit a big spell while on lots of life and you win, grats. Mostly however you will hit lands and middling things that do not help enough to offset the risk of playing Nashi. A card with an obnoxious ceiling but lacking the average performance to go with it.
Network Disruptor 2
Here is a filler support card if I ever saw one. Low power but also low cost and lots of types and things going on!
Hinata, Dawn-Crowned 3
Decent power level and cool potentials but overly narrow for most applications. I want to cast a big spell with lots of targets on the cheap with this. Sadly, I don't ever want to see this in a cube draft!
Discover the Impossible 6
This may be a little on the narrow side for drafting cubes but the power is not lacking at all. This is at worst an Impulse looking one card deeper for one more mana. Supreme Will was weaker on the card quality side and still used plenty. This then has the ceiling of finding a 2 drop you wanted to play and playing it for you turning this into effectively a one mana Impulse for five. Seems cute in storm decks where you can reduce the cost and get extra storm count on top of your card quality essentially for free. This is a very powerful little card that reminds me a little of Frantic Search, obviously no where near as abusive but still. Sadly I don't think enough cube decks have a high enough count of cheap instants to make this have a good enough average performance but it is pretty close just because it has such a reasonable floor.
Greasefang Okiba Boss 2
The kind of card you could partially build a vehicle deck with and around if such a thing is ever looked worth doing.
Shigeki, Jukai Visionary 2
Very cool card but rather more on the EDH sort of speed than that of cube. The ramp mode is cool but just too slow. If the ramp were quicker/cheaper then the channel mode would then really push this card with it's potent late game effect.