For my oppinion the Wasa is not worth the PvP marks for sailing in open world.
For a PortBattle it makes sense because the much lower BR. But you question was is the wasa good enough compared to a Bellona in the Open World -> For me definetly not mainly the HP that are to low... and if i remember right, the bellona was faster but turns much slower... So if the wasa would be faster and has slightly more HP then now it would be better...
PS: Was there already a buff for the wasa within the last patches then ignore my comment