So I've tried for quite a while to craft some sort of mana/color system to tie terrain to mana and to caster characters and the matching colors as well, but haven't had any luck. While I'm beginning to accept that druids cast druid spells, not green spells, and warlocks cast warlock spells, not black spells, etc but I am really stubborn and don't want to completely let the flavor distinction to fall to the waist-side.
Does anyone have any stories (actual or hypothetical) about how they did or would DM and keep it in the storytelling?
I imagine not every MTG savvy player will know to do things like go and decide on a color for their character to adhere to and avoid learning or preparing spells uncharacteristic of their character's chosen color, (at least until developing their character to grow into a 2nd color) or to match colors with races or anything like that, and that's saying nothing about whether they would be able to identify what spells fall into what color categories. Plus, there could very well be non-MTG players who might play and understand little to nothing.
All I can manage to consider is just "as you begin to cast your spell, you feel your connection to the islands/coasts you've encountered in the past, and your body glows with a blue light... okay, you cast the illusion spell. Don't go casting fire spells now, they're Red. You're a Blue Mage."