Hello there! Please note that this idea is CRAZY, but crazy is good, no? Anyway, here is my idea...
Let's start off with a quote from the Press Tour:
"Huojin is a philosophy among the pandaren that inaction is the greatest injustice, and that there is no shame in defending one's homes and loved ones regardless of cost. Those pandaren who follow the path of Huojin are allies of the Horde, and are represented by Ji Firepaw, a staunch adherent of this philosophy"
Now, everything is fine, it suits the Horde and all. HOWEVER, in the past this way of thinking has lead people to their doom. The best example? None other than Arthas!
Firstly, The culling of Stratholme resembles the incident with the ship in the wandering isle greatly. Similary to Aysa, Jaina was hesitant to act, suggesting Arthas (Just like Ji) that they should plan everything out. Arthas, on the other hand, knew that if they wait, the plague will spread across Azeroth and most likely kill everyone (Just like Shen-zin Su). This has separated Jaina and Arthas, with Arthas taking action immediately and succeeding in stopping the plague from spreading.
Secondly, Arthas, Muradin and Frostmourne. Once again, Arthas acted as Ji and Muradin acted as Aysa. Here is a quote from Arthas, just before he aquired Frostmourne :
"Now, I call out to the Spirits of the place. Whatever you be, good or ill or neither or both. I can feel you here. I know you are listening. I'm ready. I understand. And I tell you know - I will give anything, or pay any price, if only you will help me save my people."
I don't know about you guys, but this sounds just like something Ji or any Huojin follower would.
Metzen has constantly reminded us that the expansion is all about the pandaren teaching balance. With Ji joining the horde and Aysa joining the Alliance, the balance is broken. Mark my words, Ji Firepaw will play a big part in future patches, and will probably (most likely) play a part in Garrosh's downfall. Maybe Ji will pass his philosophy down to Garrosh? Just like Arthas, Garrosh won't have any evil intentions other than saving and protecting his people, even if the price of it is dabbling into fel energies for example.
And... I know that I will hate myself for saying this but... The old gods will play a part in this... Just as the Old Gods play a part in everything in the past, including Arthas, we can be assured that they will play a part with Garrosh, even if it's not direct corruption.