we all know forcefield denies micro, and is too game deciding, and is spammable. in fact, this skill is the protoss version of fungal as it denies micro, traps units for inevitable death, cannot be countered when casted. Is it imbalanced? Of course! if fungal gets nerfed, so should this skill too.
marines... the only zerg counters to marines are banelings and infestors. if fungal gets nerfed, marines force auto gg against zerg. marines+split against banelings, gg.