(by cards designed)

Shazzeh – 29
ParadOxymoron – 29
Echo_Robin – 24
TPmanW – 21
chinkeeyong – 21
Cato – 19
Mown – 18
[[Reprints]] – 17
Confused – 14
Dudibus – 8
Steinhauser – 7
Tevish Szat – 7
Ace of Moxes – 6
Knifethrower – 6
storyteller – 3
Fakeartist – 3
altimis – 3
thatmarkguy – 3
Silly – 2
Hello World – 2
LilyStorm – 1
Effigy – 1
RuwinReborn – 1

17 reprints is way too many.

• Blue has way too many 1-mana spells. 6 of the 9 cards in the set that cost are instants or sorceries, and of those, 3 are cantrips. There's also another 1-mana cantrip in Black in Mindshivers.
• There are seven common black cards that cost
• Black only has two common 2-drops
• Black only has three 4-drops, two of which are Horde beneath the Ice and Winterplague Wendigo, which are way too similar
• Between Living Bonfire, Sandpit Wurm, and Sunfury Haint, Red has too many big bois at common.
• Outside of common, however, only one of red's cards costs more than 4.
• Green, on the other hand, has a ton of common 1-drops, but not a single common that costs 6 or more.
• More than half of our uncommon artifacts are medium-cost equipment
• 1/4th of our common artifacts are Grey Ogres

• Glyph of the Guardian is the only white card with engrave. This may be fine, but given how every single other engrave card in the set is in U/R (besides Control Bug which should probably be cut for simplicity's sake anyway, so that they're all on spells), it's weird that the engrave cost is when it's in the color you'd be most inclined to splash in any sort of engrave-y deck.
• If Control Bug and Glyph of the Guardian were to be cut, there'd only be seven cards with engrave left in the set, with only Written in Steel and Insult to Injury at common.
• Again, there are way too many 1-CMC instants/sorceries. Five of them are blue commons, and another three are black commons. Even with an incredible amount of support in these two colors for an "instant" deck, which was supposed to be in U/R anyway, this is still probably too many.
• Black only has one rare instant/sorcery. This may be fine.
• Black and red could probably each use one fewer creature at common.
• If you count spells with engrave as creatures, red has the most creatures by far.
• Of the 8 spells with engrave, 7 are instants. Raid the Ruins is the only Sorcery, and should thus probably be bumped up to being an instant, perhaps at the cost of a color intensity increase.
• Green's creature:noncreature ratio is only 50% at common, which is one card less than white's, red's, or even black's in common. At uncommon, however, this ratio is 8:3, making their overall creature:noncreature percentage even higher than white's. So perhaps some of the uncommon creatures should be swapped in rarity with some noncreature commons, or color-shifted into White, since MaRo is always talking about how Green should have bigger creatures than White does, but not as many.
• There are no uncommon green noncreature enchantments. This may also be fine, but it's supposed to be the secondary enchantment color behind white.
• Druid's Heirloom is the only common artifact that's not a creature.

None really, except I'm not sure Cheapshot Enthusiast and Icy Whisper belong in black. It's ironic that I should think this, as I fought adamantly for their inclusion when they were argued as being out-of-color when i designed them four years ago. But it does seem pretty gimmicky to put them in Black, when there are no other cards in the color that care about spells, and when the former would fit so well into Red and the ladder so well into Blue. You wouldn't even need to change the names. Also, Barren Manifest is a weird card that I feel doesn't belong in the set, and if it stays it definitely shouldn't be an enchantment. That wasn't on the original card; I made that change myself later. But we already have Quiet Factory and The Manufactory as man-lands, and probably don't need a third. I don't feel like Written into History really fits into the set, either, as its interests are at odds with the rest of the set.