I think the scene will be flooded with good technical level of producers over the next 2 years. Many, many, many tracks will be released by a whole house of dutch, italian, UK and german prodcuers and because so much will be comming out we will be spoilt for choice on what to buy or play. As there will be so much comming out the scene will go flat as ideas run out and the same samples are used to death.
Top quality pioneering tracks will be far and few apart. The general standard of tracks will be better than it is today but will start to become very hard to be original and a lot will sound the same. After 2 years of this I reckon about 2005/6 music will start to become more about how they make you feel or what they mean... to generate feeling and purporse to the listener.
The music will become deeper, and far more clever. They will be atmospheric and suttily have meaning to the listener. The sound will be much more than just programming of samples, it will be far more emotional and feeling based on all levels not just uplifting or euphoric. I think they will be longer tracks and more based on flow of music than be about build ups, breaks and baselines. The instruments wont change but a new way of thinking will spurn a new subgenre or way of producing. This will then peak around 2008ish until the cycle of starts again around 2010 and a new sound is sought after or thought of.
I could be massively wrong or I could be just being biased in how I want it to go... who knows... but it will be fun finding out. I hope. :)