Superpowered potions that save inventory space & make the game lots funner

It would be a great way to save inventory space and to make advanced players able to do a lot more, if you could combine separate potions on a brewing stand. For instance, speed II and slow falling II could be combined inside a cauldron and this would then be scooped up with a bottle, resulting in a combined speed-slow-falling potion. The same two effects, except you only have to drink one thing. This could be applied to every potion in Minecraft.