generally speaking, etudes by chopin and Liszt are among the most difficult. And of course, that's what they were composed to do - challenge the performer technically (and mentally!!!!).
Nevertheless, even the most difficult passsages become possible with the right approach. Remember, composers spend months, if not years polishing a single piece. As performers, we can not then be hasty with our work. A well-crafted work deserves a well-crafted interpretation.
Alsp, the proper fingering can absolve many problems. Not only that, but a careful anaylsis can shead light on a difficult piece (especially those by Prokofiev and others). How can we expect ourselves to play what we can't understand?? Moreover, try not to get overwhelmed with the velocity factor. Fast playing should be, after all, slow playing faster. That is, the clarity and cleanliness of slow playing must always be maintained- no matter what tempo. Too many performers treat speed as a monster and pieces then become different entities at faster speeds.
Finally, we need to think (I feel) of technique not only in terms of arm weight and rotation, but in terms of composer. Every composer demands different aspects from performers. The "Suite Bergamesque" may not be the most physically challenging piece, but few players present the work with the appropriate touch and soul.
Topic: Technically Challenged