Skrelv's Hive has too much going on, a great tragedy. Toxic's not spelled out, Poison isn't supported in my cube, etc. I would have certainly played the card if it simply made 1/1 tokens that can't block for a life a turn without any other abilities, but unless I go into poison (a very unlikely scenario), this is too much additive distraction for me.
Mercurial Spelldancer is lovely for tempo decks and seems fun but I don't like it enough at this moment to justify the novel sprawled across it, especially as I'm going through an audit of my cube with a word count consideration.
The Eternal Wanderer is a great walker and a compelling top-end for white that feels on-color more than a creature-based finisher. I think I prefer 6 MV Elspeth for nostalgia reasons, and don't really want two planeswalkers at this cost in the color at all, so I'll likely skip it....while picking a copy if it's cheap for my on-deck binder.
Melira, the Living Cure has the same problem as the Hive, as you alluded to, Train. Neat card, though! And looking forward to the additional art styles for this one. I loved the original Melira art, but this one doesn't look like the same character.
Other fun cards:
An equipment-matters card that clearly represents the archetype's inclusion in your cube without being totally embarrassing otherwise. A delightful option for my reject cube.
I adore this card. This is the kind of repeat reanimation that feels fair but still powerful, and is priced just right to not be oppressive. I don't think it'll make the cut with the current suite of black 3s I'm running, but I do like how it incentivizes drafters to play a specific shell for reanimation.
I'd rather have
Glasspool Mimic as my 3 MV "creature you control"-restricted clone, but this is a worthy contender.
Grazilaxx, Illithid Scholar has not been as popular as I'd have liked, and this plays a similar role, while also having drafters consider artifact synergies. A lot of text, but thankfully it's broken up into easier to grok parts. Potential consideration at the very least.
My clear favorite of the spoilers. I took out
Crucible of Worlds a few years ago to prevent locks with
Strip Mine and because my 720 no-dupes list was too big to support fetch land strategies with it, but there are still decks that want that effect. Conduit not only serves those decks, but gives you your choice of gas every turn if your deck is suited to run the card in the first place. I love having this effect confined to green, love playing cards from my graveyard, love that it's an artifact, love the callback, love everything here.
I've kept
Thrun, the Last Troll in my cube for nostalgia reasons for my draft group, but I think they'll forgive me if I upgrade him here. I don't like how uninteractive he is (at least the last one made you hold up mana) but he can't stall out on the defensive anymore, and the average quality of creatures has zoomed past where Thrun was 13 years ago now. I don't run
Carnage Tyrant because of how he limits gameplay, but I can make an exception if it's just one card in 720.
I think I've cubed with every Masticore to have come before this one at one point or another, and while I've been sad that none have stuck, this one just might have what it takes.
RG goodstuff. I like it. Reminds me of
Voltaic Brawler but without the added complexity that comes with Energy. It's not better than
Klothys, God of Destiny but I think it'll make for a better cube environment than the god.
I don't run a powered cube but this still is deeply appealing to me, the spoiler that's got my mind racing the most. A good % of decks in my cube would love to convert one of their lands into a copy of their
Phyrexian Fleshgorger or
Wurmcoil Engine in the lategame, and that's not to forget the mono-colored/aggressively drafted aggro decks who could use a second copy of an equipment or a
Blade of the Oni when they flood.
Lots of fun cards! Yay Phyrexia!