Pixel art feature suggestions

[Fabian42]

I wanted to use this website for vertical pixel art. "Gneiss name" created a sheet of average colours of blocks, so I thought it would be easy to import it all as custom blocks. But actually, the website only lets me select colours from a dropdown of Vanilla map colours, which is probably not even enough for modded Minecraft pixel art and definitely not for newer versions of Vanilla. It would be better if the user could input RGB values for the custom blocks.
Also, for a huge list of blocks like this, it would be nice to have an input feature where I can upload or paste a text file with the block name and RGB values.
And the ultimate feature for this would be a dedicated pixel art mode that already includes all the colours from the spreadsheet, lets me select top, bottom or side texture (or even cardinal directions, in case of observers, fletching tables, etc.), include/exclude animated textures, maybe even filter by transparency, light and so on.