Tuskorch actually looks like it could be pretty defensive, despite being weak to some of the most common moves in the game (Surf, Earthquake, Stone Edge, Shadow Ball, Crunch). It actually has the right moves in order to make up for it: Lava Plume, Will-o-Wisp, Calm Mind, Reflect/Light Screen, etc.
At least it can beat the other Fire starters, as long as they aren't carrying Stone Edge and/or Earthquake.
A decent SubCM set would make this Pokemon somewhat formidable:
Tuskorch @ Leftovers
Bold / Blaze
EVs - 216 HP, 252 Def, 40 SpDf
~Lava Plume
~Power Gem/Grass Knot/Earth Power/Hidden Power [Elec]/[Dragon]
~Calm Mind
~Substitute
The second move is up to preference; whatever you prefer NOT coming in to stop you. Power Gem hits every other Fire Pokemon for at least neutral, and hits flyers (like Gyarados!!!!) for SE, and isn't resisted by Latias; whilst HP Electric would hit Gyarados harder, it leaves you wide open to Dragons and Swampert, who could Roar you away without a second thought; Grass Knot hits Swampy, and nails other Water types pretty well, and trips up incoming Rocks and Grounds; Earth Power hits Fire types harder than Power Gem, and gets Heatran on his x4 weak, also hitting Tyranitar for SE; or, you can play it extra-safe by using HP Dragon, hitting every Pokemon for at least neutral damage, except for Heatran.
Trick Room sweeping looks like a fun idea:
Tuskorch @ Life Orb
Quiet / Blaze
EVs - 224 HP, 32 Def, 252 SpAt
(IVs - 0 Spd)
~Fire Blast
~Psychic
~Earth Power
~Trick Room
Trick Room and sweep with Life Orb-boosted attacks coming off 348 SpAt. Rawr. The above set is resisted only by Lunatone, Solrock, and Latias. lol @ the first two