This is a known issue, but is there any workaround? Or the only solution is to use 2.74 version for exporting skeletal meshes/animations? 
I know that we can animate whole Armature object in case of issues with root motion, but thatās not my case. I just want to get rid of this extra āArmatureā bone on top of skeleton. And I canāt find any solution besides reverting back to Blender 2.74ā¦
you could just swap the scripts for the exporter so you use the 2.74 exporter with 2.75, should work.
That worked, thank you 
For other possible wanderers: Replace entire āio_scene_fbxā folder to the one from 2.74. Itās located in [Blender folder] -> 2.76 (or any version you have) -> scripts -> addons
thatās what I used to do so I didnāt have to keep editing the exporter, anyway glad it worked:)