>>43237331Zard X's main attack is Flare Blitz, combined with a SR weakness before and after evolution, it's a shitty sweeper despite the impressive power. It has no immunities and can't repeatedly switch in and pressure for damage, and isn't bulky enough to use Fire Punch and Dragon Claw except for emergencies.
Regular Charizard hits virtually everything with Dragon Ascent and Earthquake, reserving Flare Blitz for EQ immune steels. Since it resists Steel/Fighting priority, it can repeatedly switch in during a battle versus Zard X which needs a free switch and no hazards to begin sweeping.
Zard X hits about as hard as Charizard with TC boosted Dragon Ascent, but why would you use the Mega Stone at that point versus a Z-Crystal or HDB? The item flexibility, no loss in power speed and better defensive typing make the base form better.