Plywood cut out/frameing for lighter weight?

So I am in the this is really going to happen, start making drawings, ask everyone until no one wants to talk to me anymore phase.
What issues will I find with this or is this completely fine. I was thinking of using 3/4 and cutting out sections to save weight and then frame with pine or whatever for strength in the needed areas like the door frame.
The pic... Everything in Orangey Red is plywood. the zigzag areas are cut out. For reference the smaller grid squares are 2 inches, make every 3 larger squares 1 foot.

What issues will I find with this or is this completely fine. I was thinking of using 3/4 and cutting out sections to save weight and then frame with pine or whatever for strength in the needed areas like the door frame.
The pic... Everything in Orangey Red is plywood. the zigzag areas are cut out. For reference the smaller grid squares are 2 inches, make every 3 larger squares 1 foot.