IDS HAPPING

I'd suggest removing alignments completly in favor of colours. It's a different way of looking at values and morality and conflicts too much with the traditional alignment system.

Ok, when I understood what it was I got hype as fuck.
Then I opened and read the PDF.
It's cool, but they really should go deeper. Add a few special rules to make magic closer to how it works in MtG (colors, mana and all that stuff) (though I don't know how magic works in the last D&D iteration), give rules for the gods, maybe for planeswalking. I think they need to replace alignment with color identity.
I also, probably like most of you, think they should make supplements for other planes. With one or two specific rules for each plane (influence of Innistrad moons, guild-specific classes/abilities on Ravnica...).

If they do that, they might get me to buy D&D 5e. I've got nothing against D&D, but I never really felt compelled to play it.

Alignments in D&D are absolute. Good and Evil are as real as gravity. It isn't the case in MtG. Colors hold that role. So colors and alignment are conflicting concepts on a "metaphysical" level, and combining the two would probably end causing problems on a rules level.

As I said in my previous post, I don't know how the latest DnD rules work. But I guess you could have to extract mana from your surroundings (lands) or from specific events (someone getting angry gives you Red mana, someone giving birth gives you green, etc), and you could only have as much mana as you have spell slots.

There are slots, you gain them as you level. On level 1 you might have 2 level on spell slots. That mean you can 2 level 1 spells per long rest. As you gain levels you gain more slots and more levels.

At level 5 you might have 5 level 1 slots, 4 level 2 slots and 2 level 3 slots. It would be cool to add some abilities that allow you to siphon the land for regaining slots instead of the mechanic you have now.

In 5e you regain all slots during a long rest and some classes also regain a certain amount per short rest. Problem is, as soon as you start tinkering with the base system then a lot of the balance options in the entire book change.

*taps 15 forests internally*

After i read the pdf, the totally tied color to alignment with the races.

that's dumb, but also something that can be houseruled away

I ran a long D&D Magic campaign, started in 3.5 and then converted (with great success) to 4e.
I always struggled to incorporate the color aspects into the game, while on the other hand I generally avoid alignments because I feel they don't add much to the game.
My resolution was to give access to specific traits that were at least thematically similar to the most frequent keywords, things like extra feats or minor spell abilities.
I don't think it would be hard to do something like that in 5e, especially considering how wide are feats there.

Well, this is a free PDF after all, and as they say it's a sort of companion to the art guide where there is a lot more information on the world. I think they are testing the reception before making a full-blown supplement.
5e is not my preferred game either, but once you have all the setting info in one place it won't be hard to convert.

White is Good
Black is Evil
Red is Chaos
Blue is Law
ta-daaaaa.