A one card hoser for legendary creatures? This seems a bit over the top. I mean, sure it only makes colourless; but in-set that's not even a disadvantage!

It might be much, but it's strictly worse from original Karakas aside from shifting the mana to colorless. I was going for an Academy Ruins style throwback to the OG Karakas.

I guess it's a legitimate callback - but it's a callback to legends which had power level problems; and also had a butt load of crappy legends that everyone was probably running.

In a more normal environment, this will be "For the rest of the game, opponents cannot get either of their two best creatures out of summoning sickness". Which is very strong for a 0-cost sorcery.

Making this legendary does at least remove the absolute worst abuses. Maybe it's fine. But it's sure environment warping - "Legendary" becomes a much more significant down-side for a creature to have than normal. And in draft it's almost certainly not there; so you probably don't want to plan for it? But if it comes up, ouch. Horribly metagamey.

Maybe this is fair, I'm not sure. But Karakas comes from 1994. That's a bit like comparing a card to Black Lotus to determine a card's power level.