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
Jaheira, Friend of the Forest 7.5
Calling this the green Urza might be blowing my load a bit quickly but this is a scary card for sure. It may not have the same rounded nature of Urza who has a mana sink and an EtB for tempo and value but it does have the headline act. Jaheira has the powerful scaling mana ability which is where the real brokeness comes from. Further to that Jaheira is only three mana. The main thing to note here is that it is tokens and not creature tokens. All your food, clues, blood and other easy to come by tokens not only now tap for mana but also don't have any summoning sickness. You can go off with Jaheira the turn you make her. In a build around setting she is pretty insane. Even if cube draft I think there is probably enough token generation that Jaheira is a solid include in many decks. When a build around card offers this much power and is already reasonably well supported by other cards already in cube, much like Urza, then not only does it tend to last but it also tends to facilitate new archetypes arising. All quite exciting stuff.
Blood Money 1
Although this likely winds up costing less mana net than Wrath of God it is simply not much help when it is offline till you have the 7 upfront mana. Upsides are not really what you are looking for on mass removal, it is really just all about speed of deployment which this utterly lacks.
Gut, True Soul Zealot 3
Bit of a Grey Ogre. In the right deck it is punchy but low floor, vulnerability, and needing support are all big turns offs here.
Amber Gristle O'Maul 2
Only ever being able to draw 1 card from this in 1v1 play really limits the power making it neither very good value or tempo. Only avoiding a 1/10 rating from being a dwarf with some synergy elements.
Great Axe 1
The adventure is fine if a little narrow in application. The equipment however is very unimpressive. Lots to equip, small buff on average, and no evasion given. As such I am just running a card that is better than "Steel Sweep" and never playing this in the only situations I might have looked at it.
Kagha, Shadow Archdruid 1
Unimpressive body and a weak conditional value ability. I either want amazing value or a card with a bit more tempo to it. This is a card with three drop abilities at a casting cost where you want reach and threat not support and value.
The Council of Four 0
Far too expensive for a card that does nothing on its own and entirely relies on the opponent triggering it.
Lae'zel's Acrobatics 0
Over priced for a flicker card. Such things want to be cheap for ease of use. Ideally they want to be playable on their own too (see Restoration Angel) and this fails on both accounts.
Archivist of Oghma 4
Nice effect that will do good work against some decks. Sadly, against a lot of decks this will be a Bear with flash and get little to nothing done. There just isn't enough searching in cubes going on, especially when you are relying on your opponents to be doing it for you rather than being able to supply those triggers yourself.
Gale's Redirection 5
Steal a spell counterspell! Half the time this is Dismiss for a bit more which isn't impressive. Sometimes it it more like Deflection or Desertion which is more impressive given this hits anything. My gut says this is too much mana for a reactive disruption card even if the ceiling is impressive.
Ascend from Avernus 1
Powerful card but too narrow for cube. Either this is a combo card in which case you need to fully build around it and there are better tools for the job, or it is a value card in a deck full of dorks in which case it is way too situational and expensive.
Owlbear Cub 1
How useful, a card that only becomes good after 90% of games have ended.
Displacer Kitten 2
Very small and narrow. Not the flicker effect I am looking for. Only really getting mention as you can make this hard to kill with enough cheap instants. Even so, doubt I ever play this anywhere. For something this expensive that I am playing for the effect I want it to have more resilience to removal such as Thassa.
Horn of Valhalla 3
Neither side of this is very mana efficient. You also typically want the adventure late making it less well suited on the card. Draw this early and you have a bad equipment or dead weight in hand. Draw it late and you have some small men and a big man. Seems like it doesn't offer enough power nor is it able to offer it enough of the time. I will try this out just to make sure it is bad as there is quite a lot of card here. Not expecting anything of it though.
Emerald Dragon 2
Dissonant Wave is both over cost and too restrictive to add much pull to this card. If it did then this would be good as a big flyer is always relevant. This one might have low relative power but it is threatening, it is castable, and it is worth having if the adventure appealed.
Greatword of Tyr 6.5
Likely this is too much of a do-nothing by itself to get play but it is dangerous and highly impressive for a common. This makes attacking very comfortable while progressively powering them up. It is like Luminarch Aspirant and Frenzied Goblin blended together. Both are good aggressive dorks that push through damage and bring threat to the table. Greatsword is doubly impressive as it isn't on a flimsy vulnerable 1/1 body and doesn't need an ongoing supply of mana to tap things down. Absolutely going to test this. It has the power and suitability but it is on the narrower side of things only really being suitable for aggressive decks. It is also competing with Maul of the Skyclave pretty directly and doesn't seem to come out the better.