Mirror Vision is fine. If anything Fire's shield (and leech) needs a buffs to avoid being oneshot by blitz team.

Lightning Armor is pretty much dead against Hinata; unless your opponent outgears you. IF you survive him after his mystery wears out, you can pretty much cc him to death. Plus, with Bloodthirsty in effect, they wouldn't be immune to cc, in which case you can try chaosing them and watch Midight turns on his allies.

(Also, Lightning doesn counter all main. Water's mega heal compo can outheal his damage.)

All in all, Fire (along with Wind and Earth) need buff to keep up with Lightning (and Water). Maybe gives Fire his damage buff on ignited targets or buff his leeching.