On most solo instruments the crossfade will create some chorusing. However this is mainly because of the programmer being too lazy to do dynamics the right way - with dynamic samples. You will obtain a far better and more realistic change of loudness. Also, using Note-on velocity changes combined with CC 11 expression can be done for many situtuions (an example being how timbrally a mf sample sounds o.k. for either mf OR a p sound because it is not too bright and with simple amplitude adjustment can be used as either).
You can often use the crossfade anyway if any other instrument is playing because the chorusing starts to disappear - or become very hard to hear - when anything else is playing.