I think they added lots of new image processing tools which are useful it surely will be a workflow enhancements allowing for speed.
I like the concept of the circle sort like a pie menu on steroids + placement tool, if i’ve ot that right.
what i’d like to see is painting workflow enhancements for low poly, with layers, and fusion methods , and also an awesome workflow for creating all the different maps required for 3d easily within Zbrush without so many passages.
also, enhanced retopology/rigging tools.
however I think Z4 will rock as always.