I thought this slot (common noncreature card) could be a combat trick, and I wanted it to be at least 4 mana to drive up the cost of the gold commons a bit.

Turns out it's really hard to come up with a pump spell that's worth 4 mana while still suitable for common. I mean, Sigil Blessing is pretty awesome and is still 2 mana; and I think giving +5/+5 shouldn't be done at common (without some major hoop-jumping to make Gaea's Might get there). See also Gerrard's Command.

Other possibilities: one target gets +3/+3 and prot colour? One target gets +3/+3 and flying (cf Mighty Leap)? Target gets +3/+3 and you gain 3 life?

Is this too good now? "You thought you were not blocking a 3/2 and a 1/1, but actually now I'm going to hit you for TEN and gain ten life!" Maybe should be down to one single target but that gains +3/+3, flying and lifelink?

Really not sure. Your guesses sound plausible to me, but I agree, 2GW has to give one heck of a combat trick, and yet not be so overwhelming it dominates limited completely.

Another point of comparison is travel preparations; that was often played as "Put two +1/+1 counters on each of two target creatures" (with the benefit that you could split it across two turns or >2 creatures). That suggests that two temporary boosts of +3/+3 might be about right.

Well, other colours get stuff like "I think I've give everything intimidate" at that cost.

On the flip side - white gets anything from rot like "Gain 7 life" to awesome game turnarounds like "Attackers don't deal damage this turn"

So.. I've no idea how to judge it. Slightly better than a pair of giant growths sounds not unreasonable.

Lets playtest the current version, and see how it goes?

As an aside, we could make a Sorcery-speed common version of Overrun for . Something like "Creatures you control get +1/+1 and gain Lifelink, Vigilance and Trample."

Too good. While testing the cards today, this thing acted as a complete route. 1cc creature, then 1 CD Flybear, nothing, then Invigorating Melody on 4 and Invigorating Melody on 5 completely shut me down. The fact that I lost two creatures, was down 8 life from the two exchanges, and my opponent was up 16 life was staggering.

I'm pretty sure that the +3/+3 to two creatures combat trick was perfectly fair here, but the lifelink was just too much of a bonus. The card will very commonly read "Gain 8 life" and possibly a lot more. Sorcery speed, upping the casting cost, or reducing the pluses will easily calm this down some. In theory, G/W has always been a poor combination, so this card my be that color's Armadillo Cloak, but I'd rather wait and have that proven to me first.

OK, glad we overshot rather than undershot with GW, and I see we thought this was probably too strong but wanted to try it. And we were right, so so much the better :)

Possible tweaks are:

4WG. Inst. +3/+3 lifelink. 2WG. Sorc. +3/+3 lifelink. 2WG. Inst. +2/+2 lifelink. 2WG. Inst. +3/+3.

If it's that swingy, I think it makes sense to tone it down a bit rather than increase the casting cost: I don't know but I assume it's better for limited to have a 4-mana combat trick than a 6-mana win-the-game trick.

But any of the other options seem reasonable, which seems most interesting? I picked one at random provisionally, but does anyone else have a preference.

I remember someone leaning over our game in store and asking "What makes this card White?", and the person I was testing with responding, "Well, the boost makes it green, but the card has lifelink. That's the White part."

I found that an interesting exchange. To me, both white and green have boost (Green is better, but whatever) and this hits two creatures, so asking for both colors seems right. I don't know if the general public, however, would see that as wrong. I think it looks good like that.

White gets +1/+N and +2/+N, but never +3/+N; that's pretty much exclusively green, with only extremely rare exceptions. The idea of double +2/+2 lifelink for seems reasonable - interestingly it's a double Moment of Heroism, and I might find myself wondering what's green about that.