I always had a hard time with drawing good solid lines, they always end getting broken up midway.
Precision is key with pixel art, you want to make every dot count. It's amazing what was produced during the 90s, considering they had much smaller sprites and color palettes to work with.
I would argue that SNK's old sprites were better than what they did with KOFXII/XIII for the time it was created.
Edit: 3D animation seems to be way to go for a finding a job. While there is a of lot of good 3D works, I'll always have a soft spot for 2D animation.