One thing to consider as the flush volume gets smaller...the size and depth of the water spot must also become smaller (at least one of those dimensions!). You still want to completely evacuate the bowl with each flush, and unlike toilets of old where the bowl might have held 3-4 gallons and maybe used 5-6 gallons to flush, you can't do that anymore. So, the bowls' shape has changed in both area and depth to accommodate the smaller flush volume. At some point, while they may still work, the waste may not be covered by the water in the bowl, but it still can be evacuated during a flush. It can make keeping the bowl clean harder, but some of that depends a lot on the diet and health of the person using it. That's one reason why short-cycling the flush may not be such a great idea since it might just end up diluting things verses clearing the bowl entirely. This is also an issue with dual-flushing toilets...they want to evacuate the bowl even on a low flush, so the bowl doesn't hold as much water as a similar single flush design.
The flushometer type toilets are essentially similar to a pressure-assisted tank-type toilet in that they are using water pressure verses gravity to flush, which is slower and lower pressure.