Massive increase in the number of species with identification images and colour documentation to enable colour-based searching.
Only 6 fish remain undocumented. Almost all nudibranchs are also documented. There are also many more usable descriptions of marine snails and shellfish. That said, extra points if you find a species that is not included in this guide. Just make sure you let us know and send us the pictures!
A well-structured biology (botany) handbook with high quality illustrations.