[wanab5150]

I would remove the spring and check the actual shock travel with the control arm attached before I did anything else. Is there is a bind somewhere other than just the top of the control arm? If so, it's probably not just the top arm, but a combination of issues.
I would not cut the gusset on the control arm pivot. There should not be much (if any) side to side torque on that joint from what I see, but it has the gusset for a reason.

I'm sure you checked to verify that the control arm is does not have an off center hole where the control arm is bolted into the pivot on the frame. Does it have a specific top and bottom? Have you tried rotating the control arm 180 degrees just to see if there's a difference? Could the arm be backwards?

The rod end solution would be more sano but you would have to shorten the control arm as necessary. You probably don't need the adjustability, but regardless, the rod ends should extend the control end far enough from the gusset to allow full travel. If the strength of the box control arm is not necessary I would just replace it with a pair of rod ends and link. From the photo, it looks like a guide more than a strength member. BUT..it's just a photo. tom