It's a lovely shot and one I really like...but that sky is blown out. An ND grad would render the sky darker and probably lost detail in the darker sky areas. It would have increased contrast where it wasn't wanted. The only way to have fixed this here is to have taken a 2nd photograph but at a 2-3 stop darker exposure and then blended the highlight areas carefully in photoshop using a layer. Shadows can be pulled but clipped highlights are not recoverable. It's also important to render the sky brighter than the foreground, another error I regularly see where ND grads are employed. If an ND grad was used with the above photo, the sky would have been darker than the foreground and wouldn't look right.
It's been a while since I took the shot in question, so my memory is a bit fuzzy, but nevertheless I revisited the original CR2 file and darkened the entire exposure 1 stop in post. I don't think the tradeoff in the slight increase in detail around the sun vs. the substantial loss in detail of the clouds is worth it.
Big, puffy, tropical clouds like this are fickle and have some very fine tonal gradations. It's very difficult to layer in a darker exposure for the sun into a brighter exposure for the clouds. When I've tried it in the past, it looks like $hit. Of course, it's quite possible that my post processing skills are simply lacking.
Besides, I like the blown out sun