A use case is tangling python source code snippets containing class
definitions.

(
http://emacs.stackexchange.com/questions/31738/org-mode-babel-ensure-two-empty-lines-between-tangled-code-blocks-for-python
)

Per PEP8, the use of blank lines stipulates:
"Surround top-level function and class definitions with two blank lines."

To achieve two blank lines before a class definition, one would have to set
:padline 2.

I've written a small patch (attached here), following the contribution
guidelines on the org-mode website. The "patched" repository can be found
here: https://github.com/dangom/org-mode/tree/feature_padline

Please let me know if there is anything else I should do.

Thanks,

Daniel