I recently posted the builds for fresh 70, 2, 4, and 6 piece set so you can see the build progression. But just to make it easier, I linked the 6 piece builds below. You will find the build progression under Build Guide.
Barbarian The Legacy of Raekor Fresh 70 Build | Guide
Any guides on the best builds to get GR70 as fast as possible? As in builds that don't require as much / as perfect gear and low paragon.
Don't know what low paragon is but I've done the gr70 several seasons with generator monk. I'm usually done at around para 500-600. Done with Crippling Wave: Mangle build. I'd say that is pretty ok speed?
Gen monk takes a lot of gear and has some problems
Unless you're playing on HC i would recommend glasscannon Wu build i believe you can make it with fairly crap gear and para around 200 (there is no way your para will be so low when you will push to 70 i guess but still)
Anyways each class will depend on a gear wiz, WD and DH are 3 fastest ones no matter what i would assume (probably in a reverse order)