> The only real improvement is the replacement of the door opening button with a more intuitive door handle.
Actually, it's not an improvement. A door opening button is easy to operate with one hand; a handle needs two in order not to shift the microwave. At least all the microwaves I've seen have doors requiring noticeable amount of force to open. My guess is it's to avoid the situation in which a large dish rotating inside pushes on the doors and opens it.
The only real improvement is the replacement of the door opening button with a more intuitive door handle.