In the time-honored spirit of making threads for tweaked Air Elementals, let's welcome Bob the Dragon to the mix.

Why make a thread about this card? Well, partly it's been a slow spoiler season, what with Bad Reprints: The Gathering making all the headlines around GP Vegas. But, also, this card has some similarities with others that are either playable or marginal already.
Bob's Tall Glass of OJSo, Dark Confidant was a powerhouse in his day. There were tournament reports that boiled down to talking about how a first turn Bob was game, and that was not far off. He's fallen badly out of favor for aggressive Blue decks nowadays, but he's still very good.
On the other side of the spectrum, Dragonlord Ojutai pops up in some decks, at least in the Vintage Online league. (I remain convinced this occurs merely to spite me, but that's besides the point). Like Ojutai, this Dragon represents a combination of card advantage and a quick clock with evasion.
If Bob is playable (he is) and OJ is playable (he might be) then this Dragon is entitled to at least a discussion. Like Bob and OJ, this Dragon represents both a win condition and a source of card advantage. He's better than Bob if you want to run a deck with 4 casting cost cards, since it doesn't cost you life.
The draw ability is kind of a wash with OJ; the latter lets you dig deeper but also requires you to connect in order to get the benefit. So, if there's something in the way, Dragon draws you a card regardless.
The downside is the big deal, of course. He's worse than both OJ and Bob in a control shell because he Hell-bends you over each end step. You can't just accumulate resources to protect him as he beats down, at least without hijinks (more to come).
Similarly, the casting cost is tricky. It's harder than Bob, and probably about as expensive as OJ. While it's in a good color, getting to RR is probably harder than getting to UW, so the difference between 4 and 5 is probably a wash.
Finally, he is a slightly slower clock, taking one more turn to deal 20 damage.
(OJ's protection isn't worth a hill of beans; we play instant speed removal or Toxic Deluge. So I'm not really even thinking about that.)
Good Red Cards No One PlaysThey've been really pushing card draw into Red lately, and this card is only the latest. Chandra, Pyromaster is an amazing card that no one cares about because by the time you're paying 2RR for a walker, you have to explain why you're not running Jace / Dack instead. Red has a ton of Night's Whisper's with downside, and some very interesting card draw like Aggressive Mining and Prophetic Flamespeaker. It is only a matter of time before one of the Red draw spells breaks. Not that this one is that card, but it's another dent in the armor.
We have such a huge glut of red draw spells, though, that one wonders if there is a deck here. Can we experiment with a mono-red build, like Dragon Stompy, where every card draws cards? Is the advantage real?
HijinksDragon can't jam into a Delver shell, no, because he basically tells the control role to go sit on a tack. You dump this, you are jamming spells. But he has some interesting combinations with other cards.
Sundial of the Infinite - Avoid his downside by ending your turn with Dragon's trigger on the stack. This also combos well with terrible Time Walks like Final Fortune, or with Smokestack. (Ramp it up and end the turn with stack's sac trigger on the stack). Could there be an application for some kind of combo-ish Red shops? Someone tried this nonsense in Legacy with White Stacks, as I recall.
Donate - If you can manage to give the Dragon to your opponent each turn and then get it back, you can Hellbend their hand while drawing more cards. Donate or Bazaar Trader will get him over there, and work well with Blood Funnel or old school stuff like Illusions of Grandeur. Stingscourger gets him back after he bends them, and blinking Sower can control where he goes when. This is probably too much work.
Dragon Stompy - Before we got werewolves and flamespeakers and whatever, we used Hellbent with Rackdos Dragon and that morph-dude to get the job done. This slots right into that kind of build.
ConclusionThis card is probably not playable in an existing shell, but is close enough to Bob and OJ that I would not be surprised to see it doing something in a rogue list somewhere. However, since I'm still skeptical of OJ, and OJ is probably better in typical Vintage decks, I'm not holding my breath.
Pictures help.
-MM