Yea, the main problem I ran into was that something like this is a triangle: 
The table attempts to do a "wiggly C-shape" from Tundra down to Desert and roughly map it to the same environments that D&D 5e uses.
Your grid idea would work well if it was a "Biome Square". And maybe one could expand out the top of the triangle with more options to make it more square-like.