You said it in your second sentence.
Souls all involute (descend) with the same potential, and are all heading in the same direction, but some move faster than others. We are told in the Bible that Jesus was rather fond of some disciples, and again, it is fair to say that He was fond of all, as he chose them.
If I can argue through modern examples, we see that Gandhi, Martin Luther, Mother Theresa and Mandela, had a huge impact on the world. Again, Obama in his first term and pre presidency was said to have more support in Europe than even America. He inspired many citizens around the globe.
God gives special graces to some, by virtue of their individual Karma and commitment to a cause which uplifts mankind. They receive this, because they are receptive to it. So I have not done what Carl Lewis or Jesse Owens did, because they were called to this and given the necessary Grace.
My spiritual Teacher used to say that one perfect disciple, is better than a million, but that this perfect disciple, has to come from the imperfect ones. Still, when they appear, they shoulder some of God's work and do push mankind forward on the journey of life. The names that I have given you, are just some small examples.
So yes, we all have potential and are equally loved by God but He favours - if that's the word - all those who are eager and willing to serve and make sacrifices for the love of His Creation. for by so doing, they actually lift and elevate mankind. God-men like the Christ, Krishna and Buddha are first on the list, naturally. Abraham Lincoln, Thomas Jefferson and Mikael Gorbachev as well as Mohammed Ali, are other examples.