Where did you first encounter shaking grass?
Pinwheel Forest
And what Pokemon did you find in it?
Audino, as I almost always find.
Did you come across the shaking grass accidentally or noticed it shaking and walked towards it?
I saw it and was intrigued by it, so I walked in it, beat the wild Audino, and was amazed at how much experience it gave me.
Do you like that it uses the double battle / Victory Road battle music instead of the normal battle theme?
Yes, I think it's fitting to have different music for a different type of encounter.
Do you still run into shaking grass, purposely or otherwise?
Yes, hoping to either find an Audino that I kill for experience, or a rare Pokemon.
Do you think that there is a large enough range of Pokemon that appear in the shaking grass?
Audino's encounter rate in shaking grass is too high. They should at least spread out the encounter ratio, such as 50% Audino, and then the others are spread among the other 50%.
Would've you liked to see other Pokemon? If so, which ones?
No. I love the fact that the main purpose is saving an evolutionary stone or time building up happiness. (i.e. Leavanny, Whimsicott, Crobat, Clefable, etc.) I think Emolga should have been a regular encounter, however, instead of shaking grass.