When HDMI cable is used for monitoring it might poke your face, at least it tends to on a shoulder rig like Movietube PR.
No standard mini HDMI angled cables as the mini ports on different cameras/appliances are not oriented universally + the different port covers on different cameras will not allow a universal angled mini HDMI jack to be developed.
HDMI cable tends to strain the port on camera, no surprize here.
Port(s) on viewfinder must be aligned so that even standard cables won't distract the field of view of the camera operator and/or should not dangle onto the lens or lens accessories - therefore LEFT/RIGHT output is not good given the cable has a standard and not angled HDMI jack at the viewfinder end.
That leaves only the bottom side to be used for HDMI input and output but this solution will introduce another problem when the EVF is mounted directly onto the camera via hotshoe - it can't be that compact anymore and when tilted up or down the cables put enormous strain on the port(s).
Cables must not strain the HDMI ports on the EVF - this is the most cruicial aspect of the port placement and overall product design that needs further testing.