Before flaming me, hear me out. Both Fire and Frost has proccs or other things that make them symbiotic with certain talent choices. I'll even list them out:
Scorch (Tier 1)
Fire: Besides your choice of Mage Bomb or a Hot Streaked Pyroblast, Fire has no instant casts nor mobile choices. In addition to filling your mobile rotation, Scorch has a 1.5x multiplier on its crit chance, can procc Heating Up/Hot Streak, AND adds Ignite!
Frost: While Scorch isn't nearly as powerful for Frost as it is Fire, it's still a nice choice on mobile fights. It allows you to continue a rotation while moving when you have no BF or FoF proccs up, and you can't Pet Freeze or Frozen Orb, because Scorch itself proccs FoF proccs.
Arcane: Scorch has 0 additional benefits besides being a mobile spell. Arcane's Arcane Barrage is a 3s cooldown and is usually used during moments of moving (unless you know your charges won't expire). While Scorch does procc Arcane Missiles, every other spell that does damage does as well, so it provides no benefits over using, say, Arcane Explosion, other than being a spammable cast spell.
Tiers 2, 3, and 4 aren't symbiotic with one specc more than another as they are all situational/survival.
Mage Bomb (Tier 5)
Fire: While Fire doesn't directly benefit from Tier 5 over Arcane, it does benefit in a way in its rotation... If you glyph it, that is. Inferno Blast (aka Fire specced Fire Blast) when glyphed will make your Nether Tempest do a 50% damage AoE to ALL mobs around the IB'd target, spread Living Bomb to two additional targets (while still spreading Pyroblast (DoT), Ignite, and Combustion), and make Frost Bomb instantly explode. While both Frost and Arcane can do this, that requires the waste of a GCD while Fire uses IB in its actual rotation. Not to mention, Fire has little to no choices in Major Glyphs, making this a superb choice, especially when there are adds or AoE needed.
Frost: Any choice of Mage Bomb will greatly affect Frost as not only does it add sustained damage to one of the 'burstiest' speccs in the game, but it also proccs Brain Freeze, allowing for a free, instant, and 'considers-the-target-frozen' Frostfire Bolt.
Arcane: Other than the damage the bombs deal and the chance to procc AM (Like every other spell in the game), Mage Bombs have no additional benefits to Arcane.
Mage Power (Tier 6)
Fire and Frost: Both Fire and Frost have zero mana issues, because they aren't intended to. The only issue you'll ever run into with mana is when you use Invocation (it halves your mana regen), but you're intended to use Evocate in your rotation with it (to get the damage boost); in later tiers when we collect more gear (specifically higher levels of Haste), our MP5 will go up (since it scales with Haste), so even when we DO choose Invocation (especially as Frost, when paired with Frost Armor's 7% Haste), there won't be any issues anyways. All three choices simply beef up your damage.
Arcane: Here's where things get ugly. Arcane's Mastery, Mana Adept, makes the Mage do more damage the more mana they have. Looking at Tier 6, ALL THREE TALENT CHOICES AFFECT HOW YOU REGENERATE MANA. That alone should raise a red flag in your brains, and if it doesn't, here's why: No matter what you choose, as Arcane, you'll be restricted in one way or another.
- Invocation: Quite possibly the worst choice overall for the Mana dependent specc. It halves your MP5 (which immediately is a giant DPS loss), but allows you to use Evocation more frequently (also a giant DPS loss). The only time this would ever be a wise choice for Arcane is if a fight like Spine of Deathwing makes a comeback (and we all know how well that fight went...)
- Rune of Power: Probably the best choice, but still a poor talent overall for Arcane (like the other two). Not even going into the whole "forces you to stand still" and "needing to recast it" issues, it REPLACES evocation completely! Should you die or dip too low in your mana, there's nothing you can do to benefit much from your Mastery. Should you die as Fire or Frost, your MP5 will be too high to even matter from coming back with 20% mana.
- Incanter's Ward: The situational choice of the three, and personally my favorite, but still lacking in ways for Arcane. It has a passive effect of 65% mana regen and 6% damage, but if you use it, it will put a (fairly weak) shield on you that gives you mana as it absorbs damage and up to a 20% damage boost if it breaks (on top of the 10% damage it would give if you take 0 damage, making a maximum of 30% and a minimum of 10%). Also while on cooldown, you lose the passive effects.
This basically gives you a tough decision during the entirety of every fight (while watching mechanics, moving out of fire/stuff, and doing your rotation): To use, or not to use? Losing the 65% MP5 is definitely NOT worth the extra 4% damage you'd get if your shield takes no damage, so the shield is generally used best if there is something you can intentionally stand in, such as fire, to break the shield. A mechanic where we're EXPECTED to stand in bad fire? It just feels counter-intuitive.
All in all, Arcane not only gets no additional benefits from Scorch and the Mage Bomb, but ANY choice you choose in Tier 6 will simply restrict Arcane's playstyle while doing nothing but boosting Fire/Frost and giving them more choices (such as a nice heal from Invocation, in addition to the damage boosts of all 3 choices). While I don't have any suggestions, I'm simply trying to make people (and the developers, hopefully) aware of the problem Arcane has with the talents (most specifically, Tier 6).