having access to all five colours of mana on a two-mana artifact makes things far easier to manage
These can be supercharged ways to fuel your Tergrid, God of Fright, Waste Not, or Surly Badgersaur, to name a few
Planeswalkers only came into being in 2007, and we were working on Commander 2011 design in 2009 or thereabouts
The combination of franchises makes this ideal for crossover collectors, Commander players, or anyone who cares about their gear aesthetic
The tiny opportunity cost means you may not need a heavy defender theme to make Coral Colony viable, but it obviously helps and also provides another way to kill opponents using Axebane Guardian + High Alert untap loops
Odds on if I haven'r mention a card I think it isn't something you want in the deck or it is clearly similar and worse than something I have discussed