I really like the added islands, definitely adds that sense of depth! Of course it also changes the feeling of the scene, it is less "lonely" and "alone" now. But that is not necessarily a bad thing.
The clouds do look a bit "overexposed" or just not very thick, and in the tropics I tend to see fluffier, "wetter" clouds with a bit more gray. I'd be curious if you have adjusted the colors at all and if so whether the "Max albedo" shown in the cloud Colour tab is above 100. If so you generally want to avoid that for a realistically exposed scene.
That being said since you are exposing for the ground here, and it is a decent brightness, it's possible the sky is overexposed as a result. This is common in photography. If there is extra detail to be had in the EXR then post processing will bring that out. If not, then I'd say the clouds lack some detail.
- Oshyan