some of the WB pirates have been together for at least 20 years, that's a long time.
i don't think there is anything to be gained from a split up.
why would they want to roam the new world in lesser numbers and risk being crushed by one of the other yonkous?
i like the idea of them pursuing BB for revenge but shouldn't they try to kill akainu too for killing Ace?
we saw that brown beard immediately took over one of WB territories upon his death, so some WB pirates might go around regaining/protecting WB's turf.
so the WB may split up, put only to achieve specific goals such as:
-hunt down BB
-defeat Akanu (somehow)
-regain/defend WB territories
however they will remain as one crew, but will only split their focuses and not disintegrate into various crews.
if they split up then they will cease to exist, that's why i don't see that happening, i don't want to see the Marco pirates or the Jozu pirates. they all have WB tattoos, which tells me they will all be WB pirates for life.
however, Marco will have to do something big to gain the respect required to step in WB shoes and spark fear in the hearts of pirates and marines alike.