I've got the rhythmic control, and I know on what tone the chords will come. So that's not really the problem.It's more pure speed. It's not that I play it slow, but some ppl can play it faster, and I don't want to pick a tempo just because I can't play it faster.
Yes, that chromatic scale in the Chopin etude goes fast! I think that a desirable fingering must be based on an attempt to minimize movement of the thumb, and to think of the chromatic scale as being a sequence of several sets of notes each of which is arranged in chromatic order. I recommend the fingering (starting at the F-double-sharp below low C) as 3215432154321543213154321432154321. The third finger provides a strong start at the F-double-sharp, the next three sets of 54321 bring us to that B-sharp so all-important for the harmony; then we analyze where we want to end up -- B-sharp, C-sharp, D, D-sharp, E -- which we can finger as 5,4,3,2,1. Before that we have a G-sharp, A, A-sharp, B cluster to be fingered 4,3,2,1, and before that, a D-sharp,E,E-sharp,F-sharp,F-double-sharp cluster to be fingered 5,4,3,2,1, which leaves a C-sharp, C-double-sharp set to be fingered 3,1.
In deciding what fingering to use for chromatic scales, I find that the number of notes per minute is an important factor in deciding whether to go to the five-finger approach suggested above. If the number of notes per minute were only, say, 600, a five-finger approach might indeed sound too choppy. But at 800 or 900 notes per minute, the choppiness goes away. It feels good to play, too.