I have been struggling with this as well, although in 3ds Max, but I would guess it's the same. In most cases I have been able to reproduce the reference I am after. Sometimes the horizon in real life is very close to what CoronaSky gives.
Oher times I have had success by increasing the altitude (not rarely at its Max limit of 15000m) and also changing the Intensity. You can also ColorCorrect the CoronaSky map (for example give it a cooler temperature >6500K, to give it a unified blue tint), and maybe feed it to the Direct Override Slot, so that it does not interfere with the lighting of your scene.
Lastly, you can feed it through a CoronaTonemapControl, so that it stays consistent while changing the Exposure.
What I'm basically saying is that you can get the result you want, but usually through tweaking the Sky map. So yeah, I agree that extra options for the Sky model would be great, but I'm not sure where I would begin with that. Maybe we will see this in Corona 9, along with a fix for the problem with using Environment Overrides and Volume effect at the same time. Cheers!