This may be wishful thinking, but I don't think you have to necessarily sacrifice quality to be faster.
I don't think simplification is bad if you know the basics of what you are doing. For example, instead of gradients, if you know how shadows work you can use cel shading and it may look as good as a more detailed shading. Same with clothing folds, you can simplify them if you have a clear mental image of them. With details, if you hint them properly the brain can usually complete the idea.
At least that's the impression I get when I see these minimalist drawings from pro artists.
Please note, that I'm in no case saying that I know the basics xD