Another 5e MTG setting thread: color alignment and magic

[Threeshades]

So the plane shift Zendikar and Innistrad articles have inspired some people around here to work on some mechanics that tie MTG's color system into the mechanics.

I would like to present my approach here

This is based on the Spell-lists as colors that Laurefindel took the time to compile. This lists which spells are associated with each color. (some spells being associated with multiple colors and as a result appearing multiple times)

I wanted to make the system so that similarly to the card game, the fewer colors you use the more easily you can cast your spells but also the less varied your options become.

Alignment
One important part of my system is that the classic DnD alignments have been replaced with the five colors. A character can align with any number of colors from a single one to all 5. What exactly each color means for your alignment I don't want to go into right now. This is just important because the magic system hinges on the fact that you choose a number of colors for your alignment.

Magic
Characters use the same spell lists for their class as normal however they can only learn, prepare and cast spells associated with one or more colors in their alignment. Meaning the fewer colors your alignment includes (this only applies to spells you gain from the Spellcasting or Pact Magic class feature, features that spells to those spell lists (like Domains and warlock Pacts) and the Ritual Caster and Magic Initiate feat, racial spells and spells gained from other class features can be used as normal), the fewer spells are available to you.

To compensate for this drawback I want to give spellcasters with fewer colors other advantages. So any spellcaster gets the all the benefits from the following list given for their number of colors and higher number of colors (so a 2 color spellcaster gets the benefits for 2 colors, 3 colors 4 colors and 5 colors). These benefits only apply to spells from your Spellcasting feature, Pact magic feature, Magic Initiate feat or Ritual Caster feat.

5 colors No benefit, you cast spells the same way as a normal spellcaster in 5e

4 colors No benefit (yet, the limitation to spell lists isn't severe enough for me to come up with a benefit that is subtle enough to balance it out)

3 colors +1 bonus to Con saves to maintain concentration on a spell

2 colors +1 bonus to spell attack bonus and spell save DC

1 color Your spells gain an additional benefit based on your color from the list below.

White Spells you cast, that restore HP, restore 1 additional HP to each target.

Blue You gain a +2 bonus to Spellcasting ability checks you make as part of a spell. (like dispel magic and counterspell)

Black Undead creatures created or controlled by your spells have advantage on Dex and Cha saves and checks as long as they remain under your control.

Red Spells you cast that deal damage, deal 2 additional damage of the same type to the target or all creatures in the area of effect. (but not to secondary creatures affected that are not the primary target, such as creatures adjacent to the target of a green flame blade spell)

Green Creatures summoned by your spells have advantage on Str and Con saves and checks.

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I am not sure if these benefits are overpowered in exchange for the limited spell list. It was difficult to come up with only slight benefits that are good enough to warrant limiting your spell list, but also a stacking system that doesn't basically incentivize only two options because there is only one benefit to be gained.

I'd love to hear feedback if you think this system sounds fair to you or if a mono colored spellcaster us useless or overpowered.
If you have alternative ideas how spellcasters could benefit from using fewer colors, I'd also like to hear it.

[Threeshades]

I'm currently compiling color spell lists for each class which will probably make this easier to judge. I might have to adjust this model because mono blue clerics, non-white paladins (pallies of color?) and non-green rangers have severely limited spell selections. I expect the same to happen for warlocks in colors other than red and/or black and for mono white wizards and sorcerers, but i haven't gotten around to those classes yet.