Unless something has changed radically in the last few years, that's just not true. The torque converter will drop out of lock-up as soon as you demand sufficient acceleration (this will vary tremendously by engine - i.e. an inline four will do it regularly, a big V8 may meet most of your acceleration needs without dropping out of lockup) or tap the brakes. Torque converter with lockup have been around since 1950ish.
Having spent a decent amount of time with ZF8 speed the torque converter is almost always locked out. Throttle response and engine braking don't lie.
Edit: by the way, I looked up the ZF8 and it's available in a bunch of configurations. One of them is a wet clutch instead of a torque converter, which I imagine has to operate like an electronically controlled manual transmission. There's even an option to have an electric motor instead of a torque converter for hybridization!
It's one the of the reasons the ZF8 transmission is used in everything from the new BMW 8 series down to the Dodge Charger.