The "if at all possible or practical" is far more limiting than you might think. An around the wall layout for me would have meant dealing with two separate doorways. Even though I could design around that I still was faced with a second limitation that the room had to remain useable for other purposes. That included being able to open and close windows on the exterior walls. For the right modeler with the right space an around the wall layout may be the best option. For different modelers with different spaces around the all with a peninsula, an island or a traditional or dogbone L shaped layout may prove to be better options.
Which brings us to the "should larger curves be a goal" issue. Larger curves look more realistic and they open up operational possibilities. They also chew up a great deal of space. Moving from O-42 to O-72 is going to chew up a lot of ground that could have been used for longer tangents or other purposes, even with an around the room layout. It creates more dead space in the corners. When it comes to curves the rule shouldn't be "bigger is better". The rule should be "big as they need to be" with need being determined by aesthetics and operational requirements as well as the size of the room.
