I agree with Zappa.
M-W says creative really means something that is created rather than imitated. With enough practice, I think anybody can learn to do just about anything (of course, some people need more practice to do it). I'd imagine once you get the fundamentals down, you'd be able to play something differently...that is to say break away from the "cliche licks"
With the endless possibilities of notes this should be easy, but it's not...it takes a lot of practice. In my genre (hard rock and heavy metal)
Planetalk really helps creativity along alot because right off the bat I'm playing much differently than the scale guys.
What it takes to be creative, IMHO would be a decent grasp of theory, a good ear, techinical ability, and lots of patience...
As I said, a different way of approaching things (*cough* planetalk *cough*) goes a long way too simply because it breaks you away from the imitation mindset and more towards the inventing mindset.