Thank you for giving Ruphand a look!
That sign is getting an icon as soon as possible. I'll either patch the game or split the next update into two parts and release the first, but either way that thing is getting some work.
I've always wanted to put in a "spot mix" command that lets Brill make a potion in mid-fight, at the cost of taking up time and being left open. I couldn't get it to work when I started the project years ago, but now that I know more about RPG Maker and JavaScript, I may revisit this idea.
Sampling would be interesting to overhaul, especially given the basic code for it is like six years old now. It'd take some time to work out, but I think I have a few ideas for it that could fit right in with the existing code without requiring me to overhaul every single map's sample list.