Throwing off the color wheel takes away from the essence of the game. In order to have a game at all, you have to give each level or color (or whatever system used to classify) its own very unique distinctions; otherwise, like Yu Gi Oh, for example, anyone can play absolutely anything - not pretty and not intelligent when it comes to constructing a game.
Let's face few things:
Black should not be able to touch artifacts or enchantments. It deals with life-forces, not destruction. It thrives on harassing organic life force, hence its opposition to Green and White, the 2 most organic colors. It cannot destroy Artifacts because artifacts posses no life-force; enchantments are weird, but I doubt that they could count as "life-force." Thus the ability to destroy creatures and lands so easily comes natural. A player's hand is also a natural target because in Magic the player's hand represents the player's "mind" - a life-force in its own right; the one thing I would have a problem with is a player's library - in Magic, what does "the library" stand for? Is it another facet of a player's mind? Or what? Although Black would benefit greatly from having its own Disenchant, it would greatly upset the flavor of the color. I play Black, I long for a way to deal with those permanents...but I like Black because of its strengths as well as its weaknesses; in fact, its limitations make it what it is!
Now, the color of chaos and destruction is
Red. Artifact, land, and creature destruction is rather easy. Countering spells is not as controversial as some people think it is: its part of Red's chaotic nature. The day they give Red a straight-out counter, we can be worried, but as long as the counter is chaotic, it's actually in tune with Red's flavor. Red is also the color of direct damage because it is the color of chaos, heat, fire...everything blunt and harsh comes natural to Red's flavor: Wildfire, Inferno, Apocalypse...just to name very few. Returning permanents back to owner's hand is too suave for Red - it simply doesn't make sense; it's orderly in so many ways; it has no bluntness, no in-your-face type of effect; it's very calm and very rational. It naturally has nothing to do with Red.
Green is nature par excellence. It is natural for disasters to happen, Green is fully capable of them. But to simply drain the life-force of an organic being, such as give a creature -2/-2 penalty? That is impossible. It has more chances of destroying a creature than simply just drain away at it. In fact, the Green card you have made here can easily be made Black; make it an Instant, have it cost 3B, and there you go. There is nothing Green about it. It’s ability to destroy artifacts and enchantments was long overdo before Naturalize came into being, being the organic color, something as inorganic as artifacts are naturally despised under Green’s law. Green’s ability to destroy enchantment is attributed to the enchantment’s being a type of a life-force, an organic one, but a one that is cast – you can call it “natural magic” if you prefer; now we all know Green loves enchantments, hence the heaps of Enchantress cards it has; a color that oh-so-loves a type of card naturally can also destroy it; the same with Red-land relationship and White-enchantment relationship. Green, of all colors, is or should be capable of handling all types of permanents simply because all type of permanents are, at least in part, natural and organic, excluding artifacts, thus a card like Desert Twister is conceivable.
Next to Red, the color of extremes, we have
White, a color of extremes of its own. The difference between Red and White’s extremities is chaotic extremes for the earlier and orderly extremes for the latter. Also, next to Green, White is the second most organic of colors – its simply focused and fascinated with the more civilized and orderly parts of nature, whereas Green is primordial, mythical and ancient. In many ways, White is an extension of Green, thus they can’t oppose each other. White also is the color of developed and institutionalized religion, worship, divinity, and also pure spirituality – it can control life-forces as well as regroup and reorganize them, but it cannot drain them. White’s Circle of Protection cards, very basic and common, are a great representation of this life-force control, amongst other things. Cards like Wrath of God and Armageddon, Cataclysm and Catastrophe, are all extensions of Green’s ability to deal with anything and everything if necessary; White simply is more developed, more spiritualized, less naturalized, thus all these sweeping cards come from a more spiritual standpoint as opposed to mere “natural events.” There’s nothing more spiritually loaded, after all, then titles like “Wrath of God” or “Armageddon,” and even cards like Cataclysm and Catastrophe have some kind of “big spiritual event.” Destroying one land is not in White’ flavor: it does not imply any type of order or reorder, only destruction; Green can destroy lands because it is fully submerged in lands and, like I said, to be fully submerged and “in love” with a type of card is also to be able to manipulate that type of card; White cannot destroy only 1 land – it is disorderly; lands, to White, are the places upon which civilization, religion, and order thrives. It is different, to White at least, to be able to destroy all lands at once as opposed to simply one or two lands. White can and does pick at single creatures because a single creature can represent an anarchist who disrupts the purity and order; this is one of the reasons why White destroys only tapped or attacking creatures, and very uncommonly simply destroys a creature. Being divine, White is the color of enchantments ("natural magic"), and as easily as it can conjure enchantments, it can dismiss them. To be able to destroy artifacts can be seen, for once, as an extension of Green's hatred towards artifacts; White has nothing against artifacts and in fact can use them well (see Equipment), but also can destroy them because it is, generally, neutral to them. In my opinion, White should be able to counter something or another. It is fully in flavor because it is a part of White's ability to intervene as such; a type of divine intervention or spiritual dodging is not out of its reach. I'm not saying pure counter, just counter, perhaps things that threaten a creature or a land, or something that deals direct damage or in some way creates disorder and chaos.
Now
Blue is the most complicated color because essentially it can do things that all colors do. Blue is the color of the psyche, of the very mind that operates behind things, the nature behind the nature, the motive behind the action, the truth behind the appearance, the world behind the world. It is also the most "sci-fi" color, with time traveling and space manipulation; mostly, however, is connected to the mind. Blue’s relationship with White is that of order – Blue likes order, though not spiritual or governmental, but psychical order and harmony; Blue is the laziest color in so many ways, and also the most idealistic: it wants to just close its eyes and wish everything orderly; it doesn’t really want to partake in the physical process, just the mental; White is its best friend – in some ways, White is Blue’s lackey, but also Blue’s realistic counterpart: White does things, Blue wishes things to be done. White destroys all lands. Blue, no, it returns them all to owner’s hand instead. White destroys a problematic creature, Blue bounces it; White uses healing and protection to realistically deal with problems, Blue just closes its eyes and wishes everything denied: “counterspell,” “dismiss,” “thwart,” “final word.” Blue rivals Red’s egoism. Blue is subtle. Red is blunt. Blue is mentally orderly, Red is mentally chaotic. Blue's relationship with Black is the most psychological relationship in the game of Magic: Blue, being the color of the psyche, naturally has its dark side - the unconscious, the unfulfilled dreams and fantasies – Black does a lot of the things that Blue, deeply, would want to do as well: completely possessing its opponent’s mind. Blue will not admit it because in part it wants order and peace, and Black’s tendencies are very not White. Blue is the most tragic color: it is torn between darkness and light. A lazy color has no way of generating mana, although I assure you that it would love to generate mana just by “thinking” about it. If you think about it, everything is possible in Blue – a card that generates mana is actually conceivable simply because, with the appropriate drawbacks, Blue can wish anything into reality. I can see a card like this:
[Blue mana generation card][2U]
Instant
Add UUUUUU to your mana pool. Skip your next turn.
This card is legitimate, as a matter of fact. It skips time to gain everything here and now. The 6 mana is the double of 3, so it doubles its assets today by psychically manipulating and reordering the time. Legitimate enough, but still too powerful.
The bottom line is, the colors are very complex and I don’t think enough can be written about their relationships to each other and why such relationships exist; also a lot can be added or even subtracted from a color to make it more unique and distinct. I mentioned White’s ability to counter things, and that’s one of many. To “blur the lines,” so to speak, is to kill the game. The game only exists because of its distinct and limiting elements; if every color did everything, albeit for a different price, it might be interesting for a while, but in the long run it would debase the colors, eventually equalizing them, and thereby ending the game.
That. Was. Long. Sorry.