You should have a good look at video timelines. In fact I think it is the preferred way to go with line animations, because of the smooth movement and onion skin capability. It plays up big time when you use the movement tools, with misbehaving anchor points, arbitrary un-asked for zooms, and all sorts. Really not a good experience.
We have a fortnightly thread we call Something For The Weekend in which a starter image is provided, and people can make what they like with it. It's a lot of fun, and all are welcome. The current thread has a pebble beach, which I thought I could make a kaleidoscope with, and Photoshop drove me crazy trying to make it work. I ended up doing it with After Effects, and stitching the clips together with Photoshop. (Bottom of this page)
There is a useful extension for doing line animations with Photoshop. It's called Animdessin 2, but I am not finding it on the Adobe Exchange page, and I think it _might_ now be called Animators Toolbar Pro.
Frame Animation in Photoshop using Animdessin2 plugin - MDS
There are options don't forget. Krita, for instance, is very capable, and I believe it is also pretty good at line animations.
Good luck, and please show us what you create.
... View more