It's one of my favorite games of all time. I adore the soundtrack as well. This song...Also, since I know you like Kill la Kill, you may be able to appreciate this
If it hadn't been strictly used as a plot device, then I don't think it would have been nearly as much of an issue. To be fair, the idea that we can bend the energy within us has existed since we learned about chakras, chi, and spiritual energy. All of which have been since Earth.
-Spiritbending
-Spiritual projection (and yes, the vines and Spirit Korra count)
-Energy sensing
-Jinora, Queen of the Fairies
-Removal/restoration of bending
-Fuck, even healing using water counts
-The Spirit Oasis (and there are multiple)
-Straight up bending spirit energy (Giant kaiju lasers and Kuvira's spirit weapon)
-Firebending can act as a catalyst for energybending, as seen by the one priestess that assisted Korra in Spirits when she was sensing the damage to Korra's Avatar spirit.
Fuck energybending, it's been the cause of so many of my headaches when watching the show. It's my number 1 issue with the Avatar series.
Every single plot device or unexplained moment is always energybending. In fact, for whatever reason, water seems to be a catalyst for energybending. Water Spirit Aang, spiritbending, healing, Spirit Oasis's...it's all either because of chi or energybending.
In all seriousness, though. It really is all just energybending. Even Guru Pathik energybent.
Wait how did the Guru energy bend?
I don't have too much of a problem with energy bending since it is considered the 'base' form of bending. As much as we see how things like explosion or magma bending are sub bending disciplines of say fire bending, all the core elements at their center are based around the manipulation of energy.