Its only weakness is that all Fire Energy are discarded after each use of Fire Blitz, meaning you can't stack its energy cards
Outside of this attack, Regirock ex also has Regi Charge, which lets you attach up to two Fighting energy from your discard pile to this Pokmon, and can help you scale up faster to its damage-dealing move
Big spells are going to be very juicy for this, of course, but also small things like counterspells and other interaction will get the damage flowing
From my point of view I wouldnt pay more for a card in the pack to open
Yes, the commander damage from partner with commanders needs to be tracked separately
This card saw a good amount of play in Miraidon ex variants, but without the big attacking power of Raichu V, the deck is still missing a great way to always blow up your opponent's Active Pokemon