I believe this "feature" never left beta stadium and wasn't developed any further since its release? I wonder if anyone on the Evernote developer team uses Evernote to keep his programming related notes. What this feature clearly needs:
support of native input when the cursor is inside the code block (jump 2 or 4 spaces when pressing tab, auto indent braces and blocks, auto insert closing tags, etc.
some kind of colorization wouldn't hurt (by this I don't even mean language specific colorization, just any colors for the beginning).
get rid of the weird extra top margin which gets inserted along the code block.