Copy paste / Drag and drop sub layers and mask layers.
We can already reorder sub layers... However, being able to copy and paste any sub layers/mask layers (filters, fills, levels) is kind of missing. Also, being able to drag and drop them from one layer (or mask layer) to another would be nice.
The same feature has already been suggested here : https://allegorithmic.uservoice.com/forums/261284-substance-painter/suggestions/35533555-duplicate-and-copy-paste-effects . It may be a good idea to vote for it since it has more votes.
This feature would be awesome. I've spend too much time copying values from a warp/generator to another, while editing complex smart materials i created; where it's very common to see similar masks, for instance different from each other only for a levels sublayer. This would save tons of time to everybody