Though exiling four cards a turn sounds like a lot of your deck gone, lets do the math: 100 cards, minus the commander, minus your opening seven-card hand, minus four draw steps by the time you cast this, leaves 88 cards in your library
Once a spell has been copied on the stack, its treated as any other spell and subject to the same weaknesses
This version of Kellan lends itself to a bit of a Voltron build thanks to its double strike and ability to buff your other creatures based on how equipped it is
Funny enough, "Kellan, the Kid '' is a direct reference to the notorious Billy The Kid, who was an outlaw in New Mexico and Arizona during the late 1800s
Dont get greedy, and potentially hold back digging deeper
The second pick, though, isnt nearly so easy to make