There are actually 3 bungs. The one you mentioned at 90° is actually being used now for the fuel injection sensor. It isolates the sensor the most from failure from water in the exhaust.
I don't like where I have to put the o2 sensors but there is not a lot of flexibility with them generally speaking. They just take up way too much room for their actually size.
They are essentially the same exact part that was introduced 40 years ago or so and nothing has been done to improve the flexibility of application. It's as though the manufacturers are making us all do penance and will blame it on "the Government"?
I personally think that there is plenty of room both in original manufacturers application and aftermarket to re-engineer these things and for the manufacturers to show that as a group they can have some original individual thinking and not be just another group of sterile numb nuts, however the current offerings would tend to indicate otherwise? 