There is midpoint snaps function in blender. When you activate 
snapping during transform you can use A button to add midpoints snaps. But A button wont work if activate snapping using Ctrl.
How it works:
So it will be great if developers fix this in 2.8.
Thanks!
It cool be great to be able to directly snap at mid points directly without the need of A.
Cmon guys, just fix this function