Mozart is often deemed a musical genius. If he were around today, would he be up there with the status of the Beatles and Elvis? Could his flair for "classical" music be changed for a flair in modern stuff? Could a clone of Mozart produce masterpieces of grunge/heavy metal/rock?
In Mozart's day, opera was modern/cutting edge. He was the 'modern stuff'. Some of his music was scorned as being too radical. I think it follows that if he had immerged in our time, he'd be producing music just as modern. Given the intricacies of some of his concertos, might he be involved in something more electro - dance/trance, who knows? Maybe he'd be way off the scale developing 'virtual' music? Who knows! : )
One more thing - operas were traditionally written with lyrics in Italian, but Mozart threw out the rule book and wrote operas in German - pretty radical for it's day.