Your VA can do any type of music you wanted. You can start making great music now if you have the skill. Have you recorded any songs yet using your VA ? Even your WK3700 can do some damage too. Maybe a bit easier to master than the VA.

Those other keyboards mentioned just had more sounds, more editing features, better sequencer and so on. It's like you have not even learned to ride a Toyota and then you wanted a Lamborghini. Your VA (a great arranger/keyboard) has everything it needs to create awesome songs. You probably need to stop searching for better gears and start making music. Or learn to play well and master your keyboard that you have now. Then you will be wiser and can decide the next level of purchase. Also, all the terms and jargons will make sense then.

Maybe get a good tutor to give you playing tips and start playing some songs and learn chord progressions, etc.