Corbin -  I understand exactly what you're getting at.  How to use the tools available in the digital software to help ease (not eliminate) some of the workload of drawing each line one frame at a time.

The number one piece of advice that comes to mind is don't forget about your 'copy/paste' capabilities.  If your character's right arm isn't moving for the next 10 frames, copy and past that piece of art instead of redrawing it for every frame.  If your a 'purist' (like me) your brain is immediatly screaming 'CHEATER!', but it's not a cheat. The masters back in the day would do the same thing with layered drawings - if you watch an old cartoon from the 40's or 50's you might notice a slight color shift in parts that aren't moving at the moment.  That's because they're 'hold frames' and the drawing is repeated for as many frames as necessary before it starts moving again. 

Along those lines, one thing that Toon Boom does that Flash doesn't is give you the option of keeping your lines as independent vector pieces, instead of merging everything into one object.  For example - in Flash if you draw a line using the brush tool, and then draw another line that touches the first, the two lines 'connect' and become one vector object.  In Toon Boom you have the option to turn that 'mergie-ness' off or on as you need.  Keeping the brush strokes as separate pieces helps in situations where you need to incorporate 'hold frames' but don't want to make a completely new library symbol.   For example, you have an arm in three pieces - upper arm, forearm, and hand.  In Flash you can copy the arm from one frame to the next, and then in the new frame, split the arm back into it's three pieces to do a sort of 'cut out' style movement that still gives the hand drawn look.  In Toon Boom, you don't have to continuously 'cut apart' the arm, as it retains it's segmentation from paste to paste.

One last bit of advice, don't fall into the temptation to use the tweening capabilities that are built in Flash - not if your trying to stay true to the look of traditional hand drawn animation.  That's a real 'cheat' and will SERIOUSLY lower the production quality of your project.  Other than for moving cycling animation (like walks, or wing flaps) or 'camera moves' everything should be hand drawn whenever possible.

For more tips, tricks, advice and connection to other 'tradigital' animation communities, find me on the internet as 'Sknygrydg07' - twitter, gmail, youtube, etc.

Good luck, and happy animating!