My idea for mine craft would be the ability for colored glass panes and or blocks. The main reason for this would be the fact that I (and my friends) have worked on many projects that seem incomplete because of there only being plain glass. This would, I believe, greatly increase the creativity brought to the game.

The panes would start of like the normal standard glass panes. Once you have the glass panes you would use dyes to "stain" the glass in a formation like this.

Key: X - Empty X X X
D - Dye of choice X D X ---> SG times 4 ( of colored dye used)
G - Glass Panes X G X
SG - Stained Glass

The glass would still be able to let any sort of light though (the sun, Light stones, Torches, ect.) There would be an additional effect added to the stained glass. It would enable the light coming though to have a faded image of the colored glass on the "floor/ wall/ ceiling" or other object just like you might see in a church. The angel of the light would also be able to change in accordance with the light source.

The colored glass blocks would start with again the normal standard glass block. And again you would use dye to color the blocks. The formation would be like this

Key: X - Empty X X X
GB - Glass block X D X ---> CGB times 4 (of colored dye used)
D- Dye X GB X
CGB - Color Glass block

Again the lighting effect would be the same as that of the paned glass.

This over all is my idea to better minecrart in and outside of creative mode.