So how often have you encountered aircraft doing a circuit at 1,500'?
How do you manage to descend 1,000' between the point overhead and joining mid field crosswind or downwind, and remain within cooee of the runway? Speedbrakes?
Only once or twice in the past, but we have been warned that it will be happening more often now.
The aircraft I fly has plenty of drag so descending is not an issue. I guess for more slippery aircraft they need to plan a wider turn. Although you can probably start descending below 2000' AGL safely once you are inside the normal circuit area rather than waiting until directly overhead - 1500' circuits are presumably also wider.
Or maybe a 45 degree join really is better.