Yes, she is defiantly retraining herself, but, it can also be argued that she is stronger when her and Korra are together. In fact, she is stronger. Remember, Vaatu at his full size was no match for Wan and Raava once they combined fully, in the Avatar State. Although, it was never really explained on the show how the whole Korra/Wan and Raava union works. What happens to Raava's spirit once she joins with Korra. Does Raava's essence lay dormant, deep within Korra's soul. From what we've been shown so far, this would be the most likely. can Raava control korra if she wanted to. It can be argued that when any Avatar enters the AS (continuous) that Raava is in control. Does Raava see and hear everything Korra sees and hears. Or Instead of looking at Korra and Raava as to seperetly entities, they should be viewed as one entity, because that is what they are. That much is conformed. MOST IMportantly, why dosent she communicte with korra more often, or with any other present Avatar. it was proven that they can talk to each other, when she motivated Korra, just before Unavaatu was about to crush Korra to Death. It's like when she fused with Wan, after they defeated Vaatu and Wan closed the spirt Portals, Raava sort of dissapeared. Even at the end, before wan took his last breath, it was unclear whether or not Wan actually heard Raava's statement about her being with him forever.
Another thing that dosent add up either is that, if Raava can talk to korra, why didnt she warn Korra about not opening the spirit portals, telling wan's story earlier. Raava's input could definetly of helped Korra a little when she was fighting Unavatuu. After all who else but Raava would know Vaatu's strengths and weakness better than her. They were stuck in a battle together for 10,000 years. But maybe that is too much to ask for. Another example of when Raava's input could of been useful is when Aang was lost, and wa struggling with what action he would take to stop Ozai. Why didnt she talk to Aang? At the time, it wouldn't of mattered because Aang had Roku and his past lives to call upon for help, but Wan never had past lives.
Overall, I think it should of just been explained further about Raaava and Wan/Korra's fusion, and how the 'Avatar spirit' works. What do you guys think