If there were a way to adjust the ESC's level of EMF feedback sensitivity, I think it would broaden the rpm range that sensorless would operate idealy.
Castle Creations software package and Castle Link is a GREAT thing. If it were expanded upon, it could be even better. Let's change the brain to record the data from the last several runs. How about a few ports that will allow the addition of some temperature probes to further add to the data collected? To put it in a nutshell, let's integrate an onboard data logger.
Internal construction needs to be improved. If an ESC uses a BEC that is linear, then it should be included in the heat sink construction. Most aren't. I feel like this is alot of what causes so many headaches in the BEC area.
If an ESC is going to be rated so close to it's absolute limits, then I think good heat sink construction is a must. Another thing is, just a simple fan can provide for some much lower operating temps. Heat is the enemy inside an ESC.
Heat is stress level. A cooler running ESC will provide a longer more efficient service life.