So, I'm still on a quest to staple down a mana system (5th Edition's spell point variant is a great start, but the difficulty comes with remodelling it to incorporate 2 things: 1. the notion of said points representing mana of different colors, and 2. the notion that said mana comes from terrain you've bonded with, and at a different rate than "equal to all your allotted spell points".
But what I'm currently trying to work out is what might count as a land for the sake of creating a mana bond? My current angle is perhaps size based on creature size fitting on it. So perhaps 20ft × 20ft is minimum parameters to start a mana bond. Also, atm think it could work to spend spell points (that don't refill after rest) when starting (or ending?) turn on ___ terrain of said size (the entire Gargantuan-creature-sized plot is all that terrain type, if viewed as a grid) to make a mana bond, and as a bonus action, add that 'land' to your list of currently available mana sources, then immediately add an equivalent number of mana points of the appropriate color to your mana pool for each land you choose to use. (So that turn 1 you get 1, turn 2 you get 2, turn 3 you get 3, etc)
BUT, even if that's satisfactory, I'm trying to emphasize things like "you're an Elf, while you can make choices as you progress, and you're not forbidden from using White/Blue/Black/Red mana, but you'll find Green mana easier to use as an Elf, especially an Elf Druid for example", a way to introduce this aspect and options to ADD colors to OR enhance the use of Green in this example so that it may be surmised your character is either a Green & White elf, OR a Green Elf with more Green-aligned magical prowess. Lastly, having trouble coming up with at what time IN or OUT of battle your mana pool and available mana sources should reset.
Is there anyone out there with a little insight or experience into a similar homebrew issue? I'm really on my own here, but I can't help but be bothered that playing Plane Shift: ___ doesn't do a good job of making the players feel like they're [Insert Color Here] and using [Insert Color Here] mana to cast appropriate magic. Don't get me started about the not-so-MTG Druid not being given a facelift for Plane Shift. If NOT a crazy system mechanically, does anyone have any advice on smoothly injecting description INTO player choices so that the act of casting a spell can have some meaningful background fluff in that it isn't 100% assumed random spellcasting PC (or NPC) oh-so-conveniently has ties to # of "mountains" and has exactly enough mana to cast Burning Hands for example? Perhaps merely a guideline saying "you're an Elf Druid for example, and the druid spell list comtains a number of fire/earth/lightning/mental/poisonous spells, however, you're limited to spells that as DM I identify as being "Green" spells until ___, then perhaps you can prepare and cast green spells and red spells, I'll do the roleplaying for you when it comes to the mana coming from the land and into you for you."
I fee you are going at it from too much of a card game mechanics angle. In the TCG you have X lands to create X mana, but when you read the novels, characters don't really do that, its really just for the game's economy. I would say you maybe bond to a certain specific area, for example your hometown is in the open plains so you are bonded to those plains. Or feel at home on a wooded mountain so that's where your magic comes from.
It should be a considerable size, but i don't think you should need more land to generate more mana.
Then perhaps a method of still climbing from less mana to use in one instance to more mana at later instance? Well, mana bonds are a literal part of the lore: http://magic.wizards.com/en/articles/archive/feature/mana-bond-2008-02-06 but right, I don't think most characters bond to 3 Forests so they can get 3 Green mana.
So how do you think I should flavor it and at the same time give a tiny bit of literal limitations from A. Casting their highest spells right off the bat (even if their highest level spell is 3rd level, I don't an encounter to begin with them slinging a 3rd level spell) and B. Identifying with a color of mana to the point they are *initially* unable to draw on other colors and cast spells of those colors until a condition is met? I was thinking a separate set of preset ability scores representing how much additional mana they get from lands (later I would consider permanently spending 1, 2, or 3 spell points each to start a mana bond with which to gain mana equal to that number of spent points + a modifier based on these scores) so perhaps an Elf would instantly start with scores like:
White 10 (+0)
Blue 08 (-1)
Black 08 (-1)
Red 10 (+0)
Green 12 (+1)
And if 3 spell points were paid to bond with a Forest, that Forest would give 4 green mana. But of course that's relying on the super mechanical stuff. But still, perhaps something either the ability score increases OR the opportunity to gain a feat could push a character from say, a Green Elf, to a Green/Black Elf.