I do love to do concept on characters - especially fantasy and science fiction - but my specialty is how to make a design work both in 2D and 3D.
Many design issues occur when you have a character designed in 2D and suddenly needs it in a 3D version. Something looks great in 2D, but goofy in 3D. This was the case with the TV-game character Hugo, who was originally drawn and designed in 2D, but he also had to evolve. This was a hard process because the original design was “very 2D” and looked very odd in 3D. Mistakes were made, and I don’t think the transition to 3D was ever successfully made. Looking back, I think the 3D model of Hugo in CannonCruise looks the best.
If you are designing a character for use in both 2D and 3D, I recommend that you get the 3D version right first. Sketch it in 2D and build it in 3D - and then move back to adjust and finish the 2D version. But keep in mind that if you follow the 3D version too strictly the 2D version could lose “life”, because that is what 2D are so good at giving. The result is a character that is easily recognizable as the same in each dimension.