During line training circuits were at 1000'. . (fast Cat B). . . As I was finishing this was modified to 1500' for CFIT purposes. . .
start down on say late downwind, abeam the ldg threshold drop gear & head on down (typical), that's exactly what I/we do to avoid high ROD's.
Circuit join is at 1500' then abeam the threshold, wheels down to go down. . .There was
no change to the circuit size or typical RoDs.. Once rolled out on base you were @1000 as per the training!! The bonus now was that you were all set up for a landing without the need to make configuration changes (u/c, pitch or power) - keeping more focussed attention outside for other aircraft and on the runway - especially useful at night when getting into those poorly/dimly lit runways
It's much less stressful, giving a more stabilised approach (configured from a safe downwind height to the "committed-to-land" height for full flaps selection), more looking out the window time and so I guess safer!?! . . . .
I've not come into conflict or had any hassles with the piston singles at 1000' - they tend to be closer on the downwind leg - depending on their Instructor
Looking back, I would have used this 1500' circuit in the piston twins as well.