Reinforcing themes. Blue doesn't really have one. I wanted to up the amount of spirits in blue, because there's an equipment and an uncommon creature that likes spirits... but I don't feel a need to have a large 'Spirits matters' theme. Just making sure those two cards have support.

There is, however, Aspect of Wings in uncommon, which wants you to play more instants. Fair enough. "I like instants" is a common enough blue theme.

So I chose "Instants matters, blue card" and the random generator gave me Skyshroud Elite. That's rather fortuitous. I could use another 1cc blue creature, and the ability is easy to translate to 'instants matter'. I'll probably need to toss one more common with that theme to lock it solid, but this is a good start. (Annoying aside: This card doesn't paly well with Aspect of Wings. I'm just going to shrug my shoulders. Still, that's annoying.)

Hmm... it doesn't play well with Aspect of Wings on offence. But the two together let you block-and-kill a 5/3 if that's what you want to do.

Nah... my mistake for not being more clear. It doesn't work well with Aspect of Wings because it's combining power-toughness switching with 'until end of turn' stat boosts.

I agree this card works much better on defense. It's a fine early game rattlesnake. Do you want to attack with your Grizzly Bears? Are you sure I don't have an Opt in my hand?

Even better: Do you want to attack with your Bonebreaker Giant? I may be tapped out, but are you sure I don't have a Mutagenic Growth in my hand?