Doing a series of videos where you mention even basic things, like how you decide on composition, the flow of lines or even how you choose which color palette to use on a theme would be extremely useful and interesting. Then you could move to more intermediate/advanced themes, like textures, brushes, etc. Also, what grabaleon mentioned.

I think having this structure to a series of tutorials makes the videos more appealing to aspiring and novice artists and will set the series apart from other tutorials which are disconnected. It will most likely require more work from your part, but this structure is something you could think over while you are waiting for your wrist to heal.

As for the theme, you are the creator of my favorite illustration of Princess Mononoke, so doing a couple videos on portraits is a must.

At the end of the day, any video from you Iconsider a treat, and you know better how much time you want to invest on this, so whatever you decide, we're on board.