Curves drawn with the pencil tool are automatically partially straightened, especially when drawing quickly. It's extremely inhibiting to a team of animators, and has persisted through versions of CC including the most recent 14.1.0.96.
Repro steps:
1. Open a new document and select the Pencil tool.
2. Pencil Mode should be set to Smooth. In properties, set Smoothing to 0.
3. Draw a line either using a Wacom tablet, Cintiq, mouse or Mac trackpad. Wait to release the stylus/mouse button and look at the representation of your gesture.
4. Release the stylus and see how Flash rounds your curve inaccurately or straightens a section of it.
5. Illustrate a variety of curve shapes at varying speeds, especially quick ones.
6. Zoom in to about 800% and repeat the drawing steps to see more enhanced problematic drawing representations.
Results: Drawing with the pencil tool is erratic and does not represent input, especially quickly drawn curves.
Expected results: The pencil tool in Flash CC should perform accurately as it did in versions CS5.5/CS6.
It also occurs with smoothing set to 20 and all the way to 100. Ink mode still modifies the line but it does so by universally smoothing it out instead. I believe Ink mode is meant to add no modification to the user's freehand lines but it appears to be smoothing it out much more. This has been tested with multiple Macs, OS, tablets and drivers with same results but I'm currently running OS X 10.10
Linking a similar issue for reference, the original question is marked 'answered', but my issue is discussed too.