Image via Wizards of the Coast LLC Nahiri, the Unforgiving Here is another excellent planeswalker that may cost you no more than 3 mana for 3 points of loyalty that will go straight into the Mardu Midrange deck with Bloodtithe Harvester

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Unlike Urzas effect, this means newly cast artifact creatures cant tap right away due to summoning sickness still, the mana generation adds up fast
There are worse 5-drops to play, so it might be worth running Ultimecia on the off chance you can pay the cost, but I dont think Id go out of my way to pick it in a draft
These will still matter
While Modern often doesnt transform overnight, there is usually some movement within archetypes in order to adjust to the metagame