The logo is based on the visual representation of the 440 Hz A note (also known as Stuttgart Pitch), which is used as the tuning standard for musical instruments. I don't like it either, but given that this logo is tied to the bi-directional MIDI 2.0 certification, it does not, by definition, replace the vintage MIDI logo.
By the way, there is a video on YouTube in which experienced designers share their impressions of this logo.
Will, I'd have to agree. The original logo had a very distinguished digital aesthetic and the new logo seems like a demotion. I don't think I'm exaggerating when that the loss of this very familiar logo marks the end of an era for the MIDI community.