The HET rules mean that more agile ships can perform HETs more safely. A Federation ship that wants to pull a one-eighty to bring its photons to bear will take three crits if it fails (135 degrees extra). A typical Klingon, only two. OTOH, the Klingon can take less damage.
HET-ing Gorns will be scary. If the Gorn fails, well, it can take it. And if it succeeds, that's a LOT of plasma coming your way...