If you are running old content, geo is mostly unnecessary. The big jump for geo was the adjustment of indi/geo fury, the meva+/mob macc- and adding indi/geo haste. Geos numbers are their trademark.
That make them excelent against ilv119+ mobs as they have stupid defense and geo makes possible to cap or get close to with geo magic.
But old content you can be capped with just rcb and maybe a minuet. You have lots of meva so you dont need to worry about mob enfeb. You have lots of macc so dont need to worry with meva down too.
All you need for old content is to cap magic haste, and both brd and geo can do that. Cor cant.
But i believe brd has a upperhand in this context. Geo is a magic dd, and brd has acess to rudras storm, so his dmg grow a lot with this.
For hard content, geo can be more suitable to close ilv gaps. Still, ilv content is meant to stack buffs, not comparing buffs.