ina nutshell, item refining will net you about 30% less minerals after summer expansion with current 100% refining skills.
for refining rocks, you will get roughly the same minerals with current skills after the summer expansion. this is with RE5 and a 2% implant
with full skills, that includes, specific rock reprocessing 5 and a 4% implant, you will be netting roughly 10-15% more minerals in refining from a regular station

in a minmitar station, its 10% more

ore compression will be increased because module compression will no longer be viable due to the item preprocessing nerf.
it will also be instantaneous and will no longer require blueprints.

tldr http://themittani.com/features/repro...revamps-summer