How Strong Are The Gorosei?

[Yoshi]

I'd say probably slightly weaker than Yonkos and Admirals.

It would be cheap if they were any stronger than that.

 

[Warmmedown]

I do not think they are strong at all. Just as strong as real life heads of state or noble families. They rule through respect for tradition/the status quo/the current legal order of the world and patronage.

 

[Captain Cadaver]

Yeah, I doubt Oda's going to add a twist of them being top tier fighters. They probably just control the world through aristocratic blood ties, much like the Tenryubito.