Did some tests with an 8-frame character animation and switched from sliding to non-sliding by setting the offset between each frame.
It works and it's more correct this way, but the result is clearly jerkier than using the sliding animation, such that i have to switch back to sliding i think.
It seems that by definition, sliding will be always smoother and would be the best solution provided that you set it up correctly. From what i understand, Deponia is using sliding walk cycles, as they are always smoother than the non-slide ones.
What i think now is that sliding animation is better for lower frame walk cycles (e.g. 8) which normally require bigger offset to move at a decent speed, while the non-sliding maybe provides better result for more frame cycles where the offset is smaller.