When hellbent in the late game, this essentially allows you to draw 2 cards per turn. Compare it to Dark confidant, and I think the discard should be in the cost. Also, merfolk looter in all colors? Do we want to make the looting a bit more inefficient with a activation cost?

I believe this is a direct port from the original set, at the time red looting was only just establish as a "thing" and its rules were still up in the air. Moving the discard to before the ":" should bring it back to its intended functionality.

As for it being too strong, Deal Broker isn't exactly pushing the upper limits of power creep and yes it is a rare, but that's mostly becuase of the trading effect not the looter ability. Besides it's "red" looting so it's not as powerful as "blue" looting.

I agree with Grim. Red is now firmly established has having no possibility to create lasting card advantage. Baring the fact I'm not sure this ought to be strictly better than Rummaging Goblin in the first place, it should use that card's templating.

What do we want most : a costly creature with free activation, or a cheap creature with a costly activation? Or both like Bloodier mentor? I think our three drop slots will be easily filled, and this would fit better with the rest of the commons as a two mana option with some activation cost. for the activation and a 2/1 body?

I feel like "1,T, Discard a card:" would be perfect.

That or some sort of conditional untap (artifact to the grave? "~ doesn't untap unless an artifact entered the graveyard since the beginning of your last turn"?)

Back when this card was made, one of the rules of Red looting was that it could get card advantage when its hand was empty. Cards like Dangerous Wager kind of express this. However, since its introduction red hasn't gotten any looters with card advantage potential. A lot of this has to do with the fact that Chandrawing has since become a popular red card advantage tool, thus reducing the need for that type of effect. While I'm personally still a fan of this kind of thing every now and then, I'm fine with moving toward the more modern wording.