Wikipedia has this to say about "new flamenco":
I tend to call this sort of thing "flamenco stew" because it is a such a mish-mash. Historically, Spain is the geographic connection that links Europe and the Middle East. The Moors invaded Spain in the 8th century AD and were not finally driven out until 1492. Some of the characteristic traits of flamenco music are because of this long influence of Arabic culture. The rhythmic intricacies of flamenco are unusual in European music and include things like a 12-beat compas that layers two different kinds of grouping. Phrases in European music tend to start with a strong downbeat (or the upbeat to a strong downbeat). Flamenco phrases move toward a strong downbeat.
Nuevo Flamenco ("New Flamenco") is synonymous with contemporary flamenco and is a modern derivative of traditional flamenco. It combines Flamenco-guitar virtuosity with musical fusion. Jazz, rumba, bossa nova, Gypsy, Latin, Celtic, Middle Eastern, Rock, Jazz, Cuban Swing, Tango and Salsa have all been fused into Flamenco by different artists to produce its sound.
Spanishy sounding things are popular going back to The Doors song "Spanish Caravan" which came out in 1968:
This so-called "new flamenco" is a style that was actually being developed long before Ottmar Liebert. We can trace its beginnings back to the early recordings of Manitas de Plata, a French gypsy. Here is a recording from 1963:
This was further popularized by the Gipsy Kings, a group of gitano musicians from southern France who, as Wikipedia says, "are known for bringing rumba catalana, a pop-oriented music distantly derived from traditional flamenco music, to worldwide audiences." Here they are:
Then there is the trio of guitar virtuosos Paco de Lucia, Al Di Meola and John McLaughlin who show how flamenco, jazz and progressive rock can all overlap:
I think that the best way to describe what is going on with this synthesis is that you take some of the flavor of flamenco, it's rasgueado strumming and percussive scale passages and some of the simpler harmonic progressions and optionally add things like latin percussion and jazz harmonies. The tendency is to reduce the expressive range of flamenco to a narrow band of tempos and a narrow range of feeling.
Is it interesting? Well, not really. The more it consists of never-ending fast scales, the less interesting I find it. Nothing quite so boring as never-ending fast scales...