When installed, the e-brake cable rides on above the top of our connector. I can't imagine that elongated holes in the center of the connector do much to add to their rigidity. That adds a huge twist compromise to the integrity of the connector and diminishes it's effectiveness.
By "huge" do you mean miniscule? That short section of the beam is now effectively a C-channel, this is not a huge compromise.
Now I agree that closing those holes and guiding the cable over would be a better solution and a little stronger, but I think you are overstating the issue. Frame sections on large trucks often have holes and openings through their sides, the majority of the loads are carried on the top and bottom surfaces of the box / beam structure.
If you were able to quantify the load this beam would actually see we could actually run the numbers, but I doubt the difference would be significant. Now, if you wanted to make this significantly stronger, make it taller, you could still put holes in the sides, it's OK.
And yes, I am a Mechanical Engineer, so, for the sake of argument lets just assume I am correct.
