This set of changes addresses a slight shift in approach to nonbasic lands, change of two Equipments and one mana rock. Just like previous deck updates there is no massive change to the deck’s strategy, these new cards simply synergize better with the rest of the deck than their predecessors.
Ancient Den, Great Furnace > Basic Snow-Covered lands
I feel like at some point these two artifact lands outlived their usefulness in the deck. They were included mainly to have more early artifacts for Puresteel Paladin’s metalcraft, however, for better or worse the amount of tutors in the deck made this redundant. For a while now I’ve felt the detriment of these lands being susceptible to mass artifact removal, without providing any significant benefit. In addition, I wanted to have a few more basic lands for tutors like Bitterthorn, Nissa's Animus.
Needleverge Pathway > Sunbaked Canyon
When choosing nonbasic lands that can produce the Boros colours I only include lands that are able to enter the battlefield untapped. There are a lot more options than there used to be and most of these lands are interchangeable. I chose to replace Needleverge Pathway because I want the option to choose the colour when I tap the land, even if it includes a cost. It is important to me to maximise the probability of having the colours I need, especially in the early game. I like Sunbaked Canyon because of the card draw. I don’t expect the ability to be used all the time, but I do believe it is better to have that option than not.
Blackblade Reforged > Commander’s Plate
For a long time I was not keen on the Commander’s Plate but it has also been a long time since I tutored for, or even used, the Blackblade. It is a good Equipment for a Voltron deck but it is overshadowed in this deck by the likes of Embercleave and Grafted Exoskeleton. The Plate is cheaper to cast and equip to Avacyn, and it can be tutored by Urza’s Saga. Not to mention the obvious benefits of protection from three colours (blue, green and black) and a good boost of +3 power. It also helped that Commander’s Plate from the Secret Lair Angel deck has really cool artwork.
Thought Vessel > The Irencrag
When I saw The Irencrag I knew I wanted it in the deck because as a mana rock of 2 mana value it is useful in the early game, but it also has the option to turn into an Equipment that provides +3/+3 which is a decent boost to power, and in turn to commander damage. I chose to replace the Thought Vessel because neither of these mana rocks taps for colour, and it has been rare with this deck for me to have more cards than the maximum hand size.
Darksteel Plate > Mithril Coat
Mithril Coat is a strictly better upgrade of the Darksteel Plate. It is the same mana cost and has the same abilities; they are both indestructible and make the equipped creature indestructible. However, for an additional 1 mana equip cost, the Mithril Coat can be cast at instant speed and attaches itself to a legendary creature when it enters the battlefield. Both of these cards could be in the deck but I do not feel I have space for both.