Pyreswipe Hawk is really solid in a mono-red artifacts shell, a shell I quite like at the moment, ever since it picked up a bunch of cool effects
Normally for a 4-drop I'd take a second turn to ramp with rocks like Golgari Signet and Rampant Growths and then drop it on the third turn, but here I may want to spend that turn casting Agent
Tempt with Bunnies and Jacked Rabbit are two premier rabbit makers
That being said, buying key cards at the bottom was a strong move in isolation, since 14 of 15 mythics have appreciated at least 10% from that point, with eight of those cards appreciating as much as 75% (LOTV, Cavern of Souls, Snapcaster Mage, Craterhoof Behemoth, Temporal Mastery, Olivia Voldaren, Past in Flames)
It used to be that the legend rule applied to any planeswalkers with the same name
That said, I personally see this card working better in the 99 than as its own commander