See Challenge # 087.
For Nicol Bolas, Planeswalker

Flametongue Dragon. Seems pretty good. The connection to Nicol Bolas is pretty tenuous, but that's probably okay given some of the cards with other planeswalkers in the name.

Not sure if this is too good :D i see rares like Serra Angel and this adds 4 damage for more mana. Maybe it's okey after all.

Okay as a powerful rare, but it seems way too good for uncommon even with an extra mana over stuff like Voracious Dragon or Thundercloud Shaman.

Current R+D standard is to make no uncommons better than Mahamoti Djinn. Is this better than the Djinn? I don't know. Maybe? I'd be willing to test it.

This seems okay to me. It's like a Flametongue Kavu. Or indeed Morkrut Banshee. This is obviously a Limited bomb, but it'd seem pretty lackluster as a rare to me. Note that Volcanic Dragon was uncommon when it was reprinted.

Hm. My first thought was, all the bits have been uncommon before, it seems costed fairly, it's a nice card, what's the problem?

But now I'm not sure. All the comparison cards listed have a hoop to jump through to get the 2-for-1. This is like volcanic dragon and flametongue kavu. Yes, it's like flametongue kavu... but better. Is that ok for uncommon? Is there a set of cards which are not broken, but aren't splashy enough for rare, but are too good for uncommon in limited? I'm genuinely not sure.

...When you put it that way, I think Wizards' approach is that if the card is too good for uncommon in Limited, then you make it a rare. A set can handle a small number of rares that are lackluster for a variety of reasons.

Come to think of it, Shivan Dragon and Archwing Dragon are rare, and they're not very rare, they're just fun and good. I really don't like that I'm arguing for putting good cards at rare, that's not as much fun, but it may be the only sensible conclusion. (Or the card could be toned down a bit and be a fine splashy uncommon, or powered up to make a splashy rare, and still be appropriate for Bolas.)

It's probably worth noting that Dragons are one of the single most beloved categories of cards to a large number of new and casual players. I think putting them at rare works fairly well with encouraging those players to keep buying cards hoping to get one. A less-than-rare Dragon is very unusual, and I think some people in Wizards have said making Dragon Hatchling at common was a mistake.

(Also, ooh, Archwing Dragon is nice with evolve creatures in the same way Viashino Cutthroat is :) )

I think one dragon hatchling is probably fine, and really really cute, as long as it stays an exception. But when I disagree with Rosewater about what's ok where, I assume I'm normally wrong :)