Where do people stand on the companions? Have you tried them out in your cubes?
Stern Dismissals
I can start by sharing my thoughts on the mechanic: Not all companions are created equal. To put Lutri in your cube is uninspired for the same reasons it got banned in commander from the get go; it's just an auto-include in all decks that can cast it. Jegantha's requirement also seems trivially easy to fulfill and promotes 3-5 color "piles". Kaheera is inelegant in several ways. Mechanically one could make a cube where Kaheera is good when built around, but that is a lot of different creature types to keep track of during the (face-down) draft. Sure, Kaheera looks like a feline beast (with the creature types to boot), but I see no distinct dinosaur features. And where do nightmares and elementals fit in this (chimeric) picture? Secondly - white's creature suite relies heavily on humans, making the card essentially an honorary green card in most cubes. Third: the card is clearly meant to be a lord for creatures of aforementioned types. But in a control deck with no creatures the requirement is also met. This seems to run contrary to the design.
Umori seems narrow for cube unless it has a high density of creatures with spell-like effects. Nekrataal being the go-to example. I may be wrong about this though. The effect is powerful but it does not push in any direction synergistically other than "draft creatures, dump your hand/ramp".
Keruga has very lopsided matchups. If you can take turns 1 and 2 off and cast hay-makers from then on out you have an exellent way to replenish your hand and win the game. If you get run over because you did nothing on the first two turns your Keruga will do next to nothing. Personally I am not very interested in this card outside of the fact that is a dinosaur hippo(!)
Zirda interests me. My issue with the card (pardon me for not being a level 2 judge), is that it is not obvious what constitutes and activated ability. Intuitively I think of abilites the card has while it is on the battlefield and the ability can be activated. Examples: Merfolk Looter Sharktocrab and so on. Cycling, I learned, is also an activated ability. Flashback and Jump-start are not (they are alternate costs for casting the spell). Embalm, on the other hand IS an activated ability though it on its face seems similar to Flashback. The same is true for Unearth. The heuristic is: is there a cost and an effect separated by a colon (tap ~ : gain 2 life, Discard ~ Blast from the past: draw a card). I fear inexperienced drafters will shy away from the complexity or misdraft based on misunderstanding about magic's intricate mechanics. If the hurdle of magic rules understanding can be overcome I am open to try Zirda
This leaves
Yorion slots nicely in to blue-white's identity of blinking and reinforces the archtype - the requirement might prove too easy to accomplish with cube having more playables than retail draft. Obosh and Gyruda drastically alters decisions in-draft as does Lurrus. People have compared it to having to do a stipulation draft - a favorite excercise of streamers - but with a tangible reward.
I wonder though if R&D at WOTC follow what's going on in their competitor Hearthstone.
All of these have been controversial. Reno is very powerful, but as with the guy (not to mention names ) who picks Dream Trawler and warps their deck around it will tell you - you win the games you draw it and you are not favoured when you don't. Baku and Genn's design tried to remedy the problem with the luck of the draw, by having their effect occur at the start of every game. (Obosh and Gyruda have the exact same requirements). They introduced their own problems with all games playing out nearly the same way with players using their hero power every turn. They were eventually banned from standard after prolonged popular outcry. I see history repeating itself in magic for the companions.
Conclusion/TLDR:
Some companions can be dismissed outright. Zirda might have some interesting applications depending on the playgroup. The rest I think require testing and might introduce interesting novelty to drafting. I do fear that the mechanic inherently makes for repetitive gameplay. The effects of the mechanic are already apparent in constructed formats. I am however interested on the community's take on its implications for cube.
Stern Dismissals
I can start by sharing my thoughts on the mechanic: Not all companions are created equal. To put Lutri in your cube is uninspired for the same reasons it got banned in commander from the get go; it's just an auto-include in all decks that can cast it. Jegantha's requirement also seems trivially easy to fulfill and promotes 3-5 color "piles". Kaheera is inelegant in several ways. Mechanically one could make a cube where Kaheera is good when built around, but that is a lot of different creature types to keep track of during the (face-down) draft. Sure, Kaheera looks like a feline beast (with the creature types to boot), but I see no distinct dinosaur features. And where do nightmares and elementals fit in this (chimeric) picture? Secondly - white's creature suite relies heavily on humans, making the card essentially an honorary green card in most cubes. Third: the card is clearly meant to be a lord for creatures of aforementioned types. But in a control deck with no creatures the requirement is also met. This seems to run contrary to the design.
Umori seems narrow for cube unless it has a high density of creatures with spell-like effects. Nekrataal being the go-to example. I may be wrong about this though. The effect is powerful but it does not push in any direction synergistically other than "draft creatures, dump your hand/ramp".
Keruga has very lopsided matchups. If you can take turns 1 and 2 off and cast hay-makers from then on out you have an exellent way to replenish your hand and win the game. If you get run over because you did nothing on the first two turns your Keruga will do next to nothing. Personally I am not very interested in this card outside of the fact that is a dinosaur hippo(!)
Zirda interests me. My issue with the card (pardon me for not being a level 2 judge), is that it is not obvious what constitutes and activated ability. Intuitively I think of abilites the card has while it is on the battlefield and the ability can be activated. Examples: Merfolk Looter Sharktocrab and so on. Cycling, I learned, is also an activated ability. Flashback and Jump-start are not (they are alternate costs for casting the spell). Embalm, on the other hand IS an activated ability though it on its face seems similar to Flashback. The same is true for Unearth. The heuristic is: is there a cost and an effect separated by a colon (tap ~ : gain 2 life, Discard ~ Blast from the past: draw a card). I fear inexperienced drafters will shy away from the complexity or misdraft based on misunderstanding about magic's intricate mechanics. If the hurdle of magic rules understanding can be overcome I am open to try Zirda
This leaves
Yorion slots nicely in to blue-white's identity of blinking and reinforces the archtype - the requirement might prove too easy to accomplish with cube having more playables than retail draft. Obosh and Gyruda drastically alters decisions in-draft as does Lurrus. People have compared it to having to do a stipulation draft - a favorite excercise of streamers - but with a tangible reward.
I wonder though if R&D at WOTC follow what's going on in their competitor Hearthstone.
All of these have been controversial. Reno is very powerful, but as with the guy (not to mention names ) who picks Dream Trawler and warps their deck around it will tell you - you win the games you draw it and you are not favoured when you don't. Baku and Genn's design tried to remedy the problem with the luck of the draw, by having their effect occur at the start of every game. (Obosh and Gyruda have the exact same requirements). They introduced their own problems with all games playing out nearly the same way with players using their hero power every turn. They were eventually banned from standard after prolonged popular outcry. I see history repeating itself in magic for the companions.
Conclusion/TLDR:
Some companions can be dismissed outright. Zirda might have some interesting applications depending on the playgroup. The rest I think require testing and might introduce interesting novelty to drafting. I do fear that the mechanic inherently makes for repetitive gameplay. The effects of the mechanic are already apparent in constructed formats. I am however interested on the community's take on its implications for cube.