Using the following rubric, I grade these thus:
Rubric
Design
(X/3) Appeal - Do the different player psychographics (Timmy/Johhny/Spike) have a use for the card?
(X/3) Elegance - Is the card easily understandable at a glance? Do all the flavor and mechanics combined as a whole make sense?
Development
(X/3) Viability - How well does the card fit into the color wheel? Does it break or bend the rules of the game? Is it the appropriate rarity?
(X/3) Balance - Does the card have a power level appropriate for contemporary constructed/limited environments without breaking them? Does it play well in casual and multiplayer formats? Does it create or fit into a deck/archetype? Does it create an oppressive environment?
Creativity
(X/3) Uniqueness - Has a card like this ever been printed before? Does it use new mechanics, ideas, or design space? Does it combine old ideas in a new way? Overall, does it feel "fresh"?
(X/3) Flavor - Does the name seem realistic for a card? Does the flavor text sound professional? Do all the flavor elements synch together to please Vorthos players?
Polish
(X/3) Quality - Points deducted for incorrect spelling, grammar, and templating.
(X/2) Main Challenge (*) - Was the main challenge satisfied? Was it approached in a unique or interesting way? Does the card fit the intent of the challenge?
(X/2) Subchallenges - One point awarded per satisfied subchallenge condition.
Total: X/25
Lorn Asbord Schutta's Nevinyrral, Urborg Lich-Sovereign
3/3 Appeal- Every psychographic loves this, I think. Johnny can run board-wipe tribal, Timmy likes big indestructibles, and Spike can draw his cards with his 5-for-1 plays.
3/3 Elegance - This card is very clear, in both direction and function.
3/3 Viability - Plays well to its colors strengths, breaks the wheel not at all.
3/3 Balance - While the deck's design might be oppressive as a consequence of the card's abilities, the card itself is not.
2/3 Uniqueness - indestructible Liches are nothing new, but the wipe payoff is pretty spicy.
3/3 Flavor - A homerun into a grand slam. I love how he plays alongside his disk.
3/3 Quality - No glaring errors
4/4 Challenge Completion - Full points for villainy
24/25 total score
ShivaBlade's Statue of the Devil King
2/3 Appeal- Very much in Johnny/Timmy's wheelhouse, a little too convoluted for Spike IMHO.
2/3 Elegance - This card is very clear in function, albeit not necessarily in deck direction
1.5/3 Viability - It's a fundamentally a hate card against aggressive strategies, so its applicability has some meta-dependent factors.
3/3 Balance - Very fair for what it does, not broken but far from weak.
3/3 Flavor - I like the feel of an evil, cursed statue spreading a passive blight on those who cross it, but also occasionally rising from its foundations to kick ass.
3/3 Quality - No glaring errors
4/4 Challenge Completion - Full points for villainy
21.5/25 Total Score
Raptorchan's The Grim Captain
2/3 Appeal- I think Johnny and Timmy like it for the untap and the tribal nature respectively, but I'm not sure this plays to spike's sensibilities.
3/3 Elegance - Card makes sense, no complaints here.
1.5/3 Viability - The ability triggering on upkeep instead of end step is a little upsetting, as it mitigates his immediate impact. I would like it more if either the untap was cheaper or the recursion happened more immediately.
2/3 Balance - A little too fair for a modern mythic. I want more "oomph" for such a cool character.
2/3 Uniqueness - Basically a more limited Sedris, but the pirate flavor is nice and new!
3/3 Flavor - Excellent! A fabulous incarnation of one of Ixalan's more enigmatic mythical beings. Immediately brings to mind all the more satisfying aspects of the pirates of the carribean films
3/3 Quality - No glaring errors
4/4 Challenge Completion - Full points for villainy
20.5/25 Total Score
MonoRedMage's Hakvel, Immolator of Cities
2/3 Appeal- Spike and Johnny like this for the City of Brass/ Arson Counter Manipulation, but I think it's not splashy enough in effect for Timmy
1/3 Elegance - The abilities confuse me a bit. I don't understand the flavor of a burning building producing somehow rainbow mana instead of just red, The phoenix is cool and appropriate, but the ultimate is also a confusing end goal. Why annex all this burnt up land?
2/3 Viability - A bit slow to do its thing, but could find a place in some land destruction/ Blood Moon type decks.
2/3 Balance - It's weird. I honestly have no idea how balanced this is. I think 5 CMC is pretty safe though.
3/3 Uniqueness - Nothing else like it exists really. It's a strange mix of stuff.
1/3 Flavor - It's not that I hate it, it's more that I don't get it. I'd love to read his lore to find out what this land-grabbing firebug is all about. I crave context.
3/3 Quality - No glaring errors
4/4 Challenge Completion - Full points for villainy
18/25 Total Score
Subject16's Rendclaw, Okiba Matriarch
2/3 Appeal- Everyone loves rats, right? (I don't, sorry.)
3/3 Elegance - Card is self-explanatory. It's mama rat, she makes more rats.
3/3 Viability - Both rats and Ninjas are very popular, and this is a good one.
2.5/3 Balance - It's fair enough, not really pushing any boundaries anywhere.
1/3 Uniqueness - Marrow Gnawer might as well be her big brother. Nothing new, not really a problem with that.
3/3 Flavor - Fits perfectly in Kamigawa, almost too perfectly.
3/3 Quality - No glaring errors
4/4 Challenge Completion - Full points for villainy
21.5/25 Total Score
netn10's Benzir of Temple Might
1/3 Appeal- Spike doesn't like drawbacks typically, and Timmy won't want to shrink his beasties. Johnny likes fiddling with counters though
3/3 Elegance - Card is pretty easy to understand, you profit if the victim survives.
1.5/3 Viability - I'd like to know how this interacts with Melira, but until then, it's 50/50.
3/3 Balance - It's fair enough, the kind of thing a 2/2 for 1 should be in a lot of ways.
2/3 Uniqueness - It's new enough, but still par for the Phyrexian course.
3/3 Flavor - Phyrexian to the core, no pun intended.
2/3 Quality - I don't like the card tag into oblivion, personally.
4/4 Challenge Completion - Full points for villainy
19.5/25 Total Score
RaikouRider's Sedris the Corpsewaker
2/3 Appeal- A little conditional for spike, a little straightforward for johnny.
2/3 Elegance - There's gotta be a better way to wrod his recursion, but it would take a smarter man than me to figure it out.
3/3 Viability - It looks like an evasive 5/5 control finisher, and that's pretty good.
2.5/3 Balance - It's fair enough, I wish it had some way to enable its own ability though.
2.5/3 Uniqueness - Sedris exists but now he enslaves the recently dead instead of comboing out.
3/3 Flavor - Fits the Sedris character better than the original in some ways.
3/3 Quality - No glaring errors
4/4 Challenge Completion - Full points for villainy
22/25 Total Score
Top 3, in order: Lorn Asbord Schutta, Raikou Rider, ShivaBlade