Youngsters are into downloaded music these days, and arranger manufactures are adapting by providing MP3 players/recorders on their boards.
Another thing is video, which is also all the rage, and some arranger manufactures are also staring to incorporate this.
Roland is probably the most advanced today, as they have developed VIMA which has everything the youngsters want, combined with a musical instrument; all they need to do now is bring out more entry level models that youngsters can afford.
As to a Roland arranger, then when the market improves I am sure we will see one, however it will probably be the last (Or last but one) before they disappear to be replaced by VIMA.
New Roland sound engines will also most likely start to be based around their sound modelling technology.
The above is OMO of course and could be wrong, so we will just have to wait and see what the future brings

Bill