Nantuko Husk argument is flawed, because nobody cares. Devoted Druid and a Quillspike did roughly the same thing, and it wasn't good enough to break the format.
That being said, this card does have utility with other cards that might be worth worrying about, and is borderline between a problem and just simply an infinite combo. People always forget that wizards does make 2-card killing combos, they just have to be very inefficient. Because of that, this guy might need to cost 5 (Or if someone goes and checks through all of the possible combination of cards this is devastating with, it might not need to cost so much.)
For the Infectee, I feel like just giving it +1/+1 is mechanically a lot more elegant. It looks a little odd, but essentially it's the same thing and the other wording could potentially have weird interactions with other cards.
For example, a card that said "Target creature with a -1/-1 counter on it gets -3/-3" would/could ask the Infectee if the spell is the fault of the encounter. You could argue that it isn't, but you could argue that it is. Also, is power and toughness lost, or just decreased?
I do like Windriding Drake, but I feel like this isn't a keyword, but rather an indicator (or whatever Threshold, etc. are)
Contract - You may pay U rather than the mana cost of this spell. If you do, it enters the battlefield tapped and doesn't untap during it's controller's next untap step.
Otherwise you can't really change around reminder text, it's confusing if it's different on each card (aside from things clearly indicated outside of the reminder, like the cost)
Undying BlaulbBR
Creature - Elemental Horror
Haste
Whenever ~ deals damage, put a -1/-1 counter on it.
~ cannot be removed from play if its toughness is 0 or less.
2/3
Yellowed Magister1RR
Creature - Mutant Cephalid Wizard RR,T:Yellowed Magister deals X damage to target creature or player and Y damage to itself, where X is the number of islands you control and Y is the number of mountains you control.
2/2
Greater Auramancer1WU
Creature - Human Wizard
Enchanted creatures you control have shroud.
When Greater Auramancer enters the battlefield, you may put an Aura card from your hand onto the battlefield attached to Greater Auramancer.
2/2
I think the point was to blink the Spirited Prayer so that you could search for multiple card. That, and it's a really handy to have in case of enter-the-battlefield cards.
Mind Engine5
Artifact
At the beginning of your upkeep, draw a card.
Exile 7 cards from your hand: Take an additional turn after this one. "I'd gladly trade knowledge for the ability to learn."
Gargantuan Shedder3GG
Creature - Wurm
Trample
Damage dealt to Gargantuan Shedder is dealt as if its source has wither. 2GG, remove X -1/-1 counters from Gargantuan Shedder: Prevent the next X damage that would be dealt to Gargantuan Shedder.
8/8
Fire-fed WhelpR
Creature - Elemental
Whenever a creature blocking Fire-fed Whelp is put into a graveyard from play, put a +1/+1 counter on it. R, remove a +1/+1 counter from Fire-fed Whelp: Fire-fed Whelp gets +2/+1 until end of turn. At the beginning of the end step, put a +1/+1 counter on Fire-fed Whelp.
0/2
I really feel like Tolarian Response is alright. I mean, it's less than Cancel, but only if your one and two drop are islands. I know everyone is too afraid to ever give blue a good counter in design, but this card really doesn't give you much room for anything other than mono-blue control.
Turn 1: land, go.
Opp: land, go.
Turn 2: land, creature, whatever, go.
Opp: land, creature go.
Turn 3: land bounce your two lands, and gain irreparable amounts of tempo.
Broken. If it didn't bounce lands, it'd be safe.
EDIT: If you knew my historial, you'd know I don't always jump to say "broken!!!" Hell, I reviewed a dozen cards without calling them that. Now this card is broken though.
Fair enough, sorry, I didn't mean for that to be a judgment about you, just about this one assessment.
In this case, I think you just missed the fact that it says X, as WUBRG points out.
That being said, this card does have utility with other cards that might be worth worrying about, and is borderline between a problem and just simply an infinite combo. People always forget that wizards does make 2-card killing combos, they just have to be very inefficient. Because of that, this guy might need to cost 5 (Or if someone goes and checks through all of the possible combination of cards this is devastating with, it might not need to cost so much.)
BBB
Creature - Demon
When ~ is put into a graveyard from play, destroy all creatures.
3/1
For example, a card that said "Target creature with a -1/-1 counter on it gets -3/-3" would/could ask the Infectee if the spell is the fault of the encounter. You could argue that it isn't, but you could argue that it is. Also, is power and toughness lost, or just decreased?
Contract - You may pay U rather than the mana cost of this spell. If you do, it enters the battlefield tapped and doesn't untap during it's controller's next untap step.
Otherwise you can't really change around reminder text, it's confusing if it's different on each card (aside from things clearly indicated outside of the reminder, like the cost)
Creature - Elemental Horror
Haste
Whenever ~ deals damage, put a -1/-1 counter on it.
~ cannot be removed from play if its toughness is 0 or less.
2/3
Creature - Mutant Cephalid Wizard
RR,T:Yellowed Magister deals X damage to target creature or player and Y damage to itself, where X is the number of islands you control and Y is the number of mountains you control.
2/2
Creature - Human Wizard
Enchanted creatures you control have shroud.
When Greater Auramancer enters the battlefield, you may put an Aura card from your hand onto the battlefield attached to Greater Auramancer.
2/2
Mind Engine 5
Artifact
At the beginning of your upkeep, draw a card.
Exile 7 cards from your hand: Take an additional turn after this one.
"I'd gladly trade knowledge for the ability to learn."
Creature - Wurm
Trample
Damage dealt to Gargantuan Shedder is dealt as if its source has wither.
2GG, remove X -1/-1 counters from Gargantuan Shedder: Prevent the next X damage that would be dealt to Gargantuan Shedder.
8/8
Creature - Elemental
Whenever a creature blocking Fire-fed Whelp is put into a graveyard from play, put a +1/+1 counter on it.
R, remove a +1/+1 counter from Fire-fed Whelp: Fire-fed Whelp gets +2/+1 until end of turn. At the beginning of the end step, put a +1/+1 counter on Fire-fed Whelp.
0/2
I really feel like Tolarian Response is alright. I mean, it's less than Cancel, but only if your one and two drop are islands. I know everyone is too afraid to ever give blue a good counter in design, but this card really doesn't give you much room for anything other than mono-blue control.
Fair enough, sorry, I didn't mean for that to be a judgment about you, just about this one assessment.
In this case, I think you just missed the fact that it says X, as WUBRG points out.
Not out of context, no, but I feel like if Affinity could take off just that much faster, Mirrodin could've been a bit more scary.