Kinetic Fist is exceptionally bad, and Pyros aren't great for melee already. If you just want extra damage on each hit, go for something with Sneak Attack and flank with another part member.
I don't know how all the gestalt crap supposedly works, but if you're set on Kineticist, use any of the other original five elements. Better Defense Wild Talents, less likely for energy damage to be resisted than fire, and better non-combat utility. Fire's main strengths are its unique infusions and combat versatility, and you're locking yourself out of the form infusions by using Kinetic Fist (Fire has the best AOE of the lot). Your attacks will not be touch attacks, either, as Kinetic Fist only adds damage to attacks rather than being an attack itself. I'm unsure of how Fire's Fury interacts with Kinetic Fist, as well (specific trumps general, but is Fire's Fury the specific overriding Kinetic Fist's general, or the other way around?).
Don't build for Weapon Finesse. Who would ever describe Boars as graceful? Fullplate and 13 Dexterity for the Dodge feat will do well. Focus on Strength for extra bonuses to hit and damage, pick up Power Attack, and rip things to shreds.
I agree that Fire isn't the best for this, but it does look cool and it won't be long before you can add Burning Infusion to the mix. Even Empower later on too.
An Amulet of the Mighty Fist is a must, and I'd suggest Ghost Touch first. You can't be too careful.
Earth gives you DR and Water gives you AC. You could do both, too. You don't have to build mono-element.
Unless you're grappling, I probably wouldn't go with Fire.
I can definitely see Earth being a strong choice. That DR is wonderful to have, and adding an extra d6 or so of Bludgeoning, Slashing, or Piercing can be really helpful.