A keyword box where you could type in a range of keywords and then drag and drop the relevant ones to individual images. This would help in keywording images from the same "Shoot that need similar but different keywords. I don't think it is unusual to have 50 different keywords that need applying in different combinations to a range of 50 images from a travel project where each image has say 30 keywords. Drag and drop would give a fast and flexible way to do it.
The other thing that would help is, as many others have already said, is larger image size