Can I just replace the circled parts (in the pic below) with a straight hose from the intake to the crank case? What is the point of that little plastic box there? It's a weak connection due to the angle that puts strain on it and it often becomes loose and seems to restrict airflow if anything. Am I missing something here?

 

I had the exact same thing happen on my Injen intake a few years ago. It just so happens that one day while at the dealership, the tech took a piece of suitable-sized hose and cut it to the right length, running it from the box to the crankcase/valve cover. It's never moved since.

The problem w/ the design is the little rigid tube that I can see in your pic (light-grey colour). It has no ridge to hold a hose + clamp and thus, the hose slips off. Just remove the rigid plastic piece and replace with any suitably-sized hose, you'll be fine.