Guardian has been op since before chronic nerfs and mostly gotten stronger since then. It currently has no weakness and can do everything better than every other class except for epi and group alac (till EoD). The fractal meta before exposed change was already 3 guardians because of their power and utility and specifically firebrand's dps in cm 100. The exposed and torment changes just made epi more easy to cheese cm 100 so pugs run 2~3 scourge for cm 100 and often don't bother to swap to firebrand or power for the rest. Pugs that skip cm 100 do not favor scourge AT ALL and power or firebrand is meta for those groups. Firebrand ramps up damage as fast as a power class but with op guard utility and is really overtuned. Heal/Quick brands give a lot of safety and the easiest quickness in the game. However, they are not op, quickness itself is op. Same with mirage or ren alac.
Here's what would need to change to fix pug fractal meta:
Quickness Max Effect Nerf
Alacrity Max Effect Nerf
Firebrand Nerfs
CM 100 Boss and Adds Breakbar Nerf
CM 100 Boss no longer travels across arena, only short runs around edge or to mid
Warrior banner nerf
Elementalist buffs
Warrior buffs
Thief buffs
Reaper buffs
Dragonhunter buffs
Herald Buffs
Scrapper buffs
Mesmer clone spawn rate buffs