In fact the rock theory isn't pointing to Peter as the head but Christ. The words little rock and big Rock is distinguishing Christ as the cornerstone and Peter as a pebble so to speak.
Jesus told Peter, you are a little pebble and on this big Rock whilst Jesus pointed to himself, I will built my church. Notice who is doing the building and who's church it is.
The reason Jesus spoke to Peter the way that he did was to stop the high mindedness of Peter from dreaming off into leadership role. In fact when he tried to make John to follow him, Jesus said what is it to you what will become of John, you Peter are to follow me. Notice the same language is used by Jesus to knock back Peter a couple of notches when Jesus used the small pebble big Rock distinction.
Jesus even spoke to Peter asking him thrice do you love me, to the point where it got on Peter's nerves. The rock theory is nothing more than Jesus pushing Peter's buttons to set him back a couple of notches. It can hardly be interpreted as succession.
Notice Jesus said he is doing the building and it is his church as the head stone.
If that is the case, then why the name change? There is no "rock theory" based on the texted that I provided. I told you the original language and how it translates. Reading the entire text Jesus is blessing Peter. And once again, if the "rock theory" does not add up, then explain why Jesus then gave Peter the keys to heaven and said "whoever you bind on earth shall be bound in heaven, and whoever you loose on earth shall be loosed in heaven."?
Where does it say that Jesus is "pointing to a big rock"? All I see is this "Now when Jesus came into the district of Caesare′a Philippi, he asked his disciples, “Who do men say that the Son of man is?” 14 And they said, “Some say John the Baptist, others say Eli′jah, and others Jeremiah or one of the prophets.”b]">[
b] 15 He said to them, “But who do you say that I am?” 16 Simon Peter replied, “You are the Christ, the Son of the living God.”c]">[
c] 17 And Jesus answered him, “Blessed are you, Simon Bar-Jona! For flesh and blood has not revealed this to you, but my Father who is in heaven. 18 And I tell you, you are Peter,d]">[
d] and on this rocke]">[
e] I will build my church, and the powers of deathf]">[
f] shall not prevail against it.g]">[
g] 19 I will give you the keys of the kingdom of heaven,h]">[
h] and whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven.” 20 Then he strictly charged the disciples to tell no one that he was the Christ"
Now you could say "well it was written in Greek, and Peter in Greek is Petros, and the word rock is Petra! Yes, because Petra is a feminine word and needed to be made masculine because it was refering to a man. However, as I said, Jesus spoke in Aramaic, and there is no masculine or feminine difference in Aramaic for the word rock. It is Kephas, which translates to both Peter and rock.