We all know that, among the Mugiwaras, everyone has a specific role and specific skills; in particular, Nico Robin is considered the only person alive who can read the Poneglyphs, since she inherited the teachings coming from Ohara.
Despite this, I’m strongly convinced that there is someone else who can read the Poneglyphs and, while we wait for their revelation, here I introduce you the 4 reasons why I think so:
1. Robin’s Father: he was never revealed, so that we can’t know exactly if nowadays he’s dead or alive and, in addition, once Robin’s mother said “I will honor my husband’s dream”; then she left in order to study Poneglyphs; for this reason, I think that Robin’s father was (and is) able to read them and his dream was to find the Road Poneglyphs.
2. Aokiji’s Mystery: once Aokiji said “Ohara hasn’t fallen yet”, so what does this mean? Going back into the story, after the Marine finished bombing Ohara, the marines went on the land to make sure there were no survivors left and also Aokiji was there; after burning down the whole island, the World Government had no reason to come back, so that Aokiji could have used his technique called “Time Capsule” on the water of the lake in which Ohara people had thrown their books in order to come back some time later and save them. We know that Aokiji’s ice can last for a very long time, such as, for example, the one he used in Punk Hazard, where it lasted for about two years although the other half of the island was burning. Moreover, as he resigned from the Marine, he could have given those books to the Revolutionary Army, which is just waiting for Luffy to meet his father Dragon in order to make Robin read them.
3. Robin’s Bounty: don’t you think that her bounty of 130.000.000 is too low for the only person alive who can read the Poneglyphs and reveal the World Government biggest secret? Even Cariboo has a 200.000.000 bounty and Robin is much more dangerous than him!
4. Robin’s Over-Role: we don’t have to forget that Luffy isn’t the only captain, Zoro isn’t the only swordsman and Usopp isn’t the only sniper, but, on the contrary, Robin is said to be the only one to be able to read the Poneglyphs, so that she has no one to surpass. Following this logic, she’s supposed to become the most valuable character of the whole series, since it will be only thanks to her if people will be able to reach Raftel, but I think that giving so much importance to a character like Nico Robin would be quite unrealistic from Oda, wouldn’t it?