For most decks, being restricted to only cards that cost three or more means that Keruga, the Macrosage has the same exact issue as Gyruda, Doom of Depths: you only get to play a single card over the first three turns of the game, leaving you in a position where you're often dead to aggressive decks (this gets even worse in older formats, which are faster and place a higher value on efficiency)
It always is a pleasure to write for them, and I hope to speak with you again soon
In fact, the top five cards on this list are all in the top ten most expensive cards in Modern (and two more cards from that top ten are in the set at rare!) So yeah, this is a pretty good roster of mythics
The problem is, youre staring at three logos PSA, BGS, and CGC and you have no idea which one to send it to
Still, Iron Hands ex will certainly make it into several decks, most notably Miraidon ex, Lost Zone Box, and maybe even Lugia VSTAR