I am curious how stark and yammy or really anyone else could stand to barrag. It seems like luck/chance that he was beaten.
Maybe its not so much the power that they have, but how they use/can control it...in barragans case...he wasnt immune to his power (ironic, but yeah whatever), hence his rank out of the espada (#2 is still high)...while as Halibal's power is her water cannon (which clashes with Toshiro's Ice) and Stark's are his hand guns(only he can use them)...
But this also questions the espadas other abilities and would/should that increase or decrease their rank?
Like Uli other form that only he has and Pumpkin Guys super sonido.