A possible solution, a possible alternative to piezoelectric arrays are the so-called CMUT probes. CMUT (Capacitive Ultrasonic Transducer)
They use the MEMS technology, so they are less expensive, so you can obtain more complex devices.
So everything can be integrated, also part of the electronics that can be used to drive or read the signal; integration is better and also the problems for instance of wiring can be solved more easily.
But in any case, complexity is limited due to the complexity of electronics driving and receiving system.