X is blub if there is a language which is more powerful than X and you can't understand that the "extra stuff" in that language is actually power, as opposed to meaningless stuff.

For example, an argument could be made that Lisp is a blub, because of the libraries problem. I'm not a lisp user myself, though I'm learning Scheme, so I don't know for sure if the libraries problem is an actual problem. But if it is, you could say that Lisp is a blub for Python, because while Lisp users are spending their time inventing a DSL that's incompatible with everything else, Python users type 'import awesomelibrary' and get the job done.

So, really, it depends on your notion of power. In pg's original Blub essay, power is Lisp-y-ness (or macros, perhaps), so by definition Lisp can't be a blub. But if your notion of power is something else, maybe it can be.