I like your thinking.
The problem I have with your example is the extreme angle you've created on that driver's side wall. Any large angle change can create turbulence. As it is, the angle I'm using is higher than I would like. You're proposing making it even larger.
Keep in mind that I'm trying to cancel out pressure pulse tuning in regards to the plenum with the larger than usual plenum volume. The shape has nothing to do with pressure pulse tuning considerations.
The mission here is to slowly expand and slow the flow of intake air by the time it reaches the first intake runner. The slower the flow, the less chance of creating turbulence and varying pressure pockets around the intake runners.
Also, the idea is to expand out as quickly as possible in order to end up with as much plenum volume as possible , but not so fast that turbulence is created.
Also, keep in mind that I plan to add a dividing flow vane, or two in the turn, after the throttle body.