To put all of my thoughts and beliefs on this subject into just a few overly simplified senteneces. I'd say that evil (which I see it to be nothing more than NON-love) needs to be exhausted. Once and for all. So we will cling to God (who is LOVE) for all eternity.
So we will truly, finally understand the supreme POWER of Love, (which IS God) and the utter futility of evil (which is NON-LOVE). We are all learning individually and as a whole, and every single life lived, EVERYONE will learn from. No life is ever in vain. No suffering is EVER unheard or suffered in VAIN. All suffering will be brought to light, and we will learn from it. In every way, shape and form POSSIBLE, we will learn the contrast between LOVE and NON-LOVE.
and we will CLING to our Wonderful Father for ALL eternity. And THAT is where the REAL learning about Him will start to take place. We'll have all eternity to explore Him. Just this natural earth is a small part of Him. I see everything in creation reflecting something of His nature. From little bugs to mountains, to majestic animals, everything. Every single person reflects SOMETHING of His nature. and that is probably just the tip of the iceberg.
In order to fully explore (and do whatever else we will be doing for all eternity) we need to first learn just WHO He is at His CORE. and that is LOVE! We would never be able to learn it without the contrast. He is thorough. This learning about love and non-love... He will let us exhaust every avenue of it. Remember, this isn't our real home.