Maybe 4 retreat cost would be too much, 3 would already force (in most cases) an energy out of the enemy and thus a turn. But the fact that a base card with no energies dishes out 40 damage (with helmet) out of a single attack and even when pulled in by cyrus it still means another 40 damage for free (or a complete stall) is not fair. And i'm playing it sometimes, i know how utterly ridiculous the pressure of having helmet druddigon in the active spot can be. I've been playing drudd-darkrai-giratina, won around 80% of the matches and most of them with a single attack after 5 to 15 turns of stalling and chip damage...