I’m done with this thread. Until someone respectable comes in here and can argue the pro’s of Physical Sun and Sky then this conversation is over.
We’ll try to miss you. Since you don’t “respect” any of us here and just called us all “unrespectable” for having different workflows and opinions, it’ll be a really painful thing to see you never post here again. It’s a thread about lighting, not some super-serious religious-belief argument or debate. Nobody’s attacking you. Get control of yourself.
However, I totally understand what you’re saying from a technical point, though. The problem is that you’re working backwards. Remember, son, that your method of lighting is what we used before the Sun/Sky emerged for mental ray. It’s not like the Sun/Sky is an old process, beaten up and overused. It’s the SUN, son. Think about it for a moment and leave your ego behind.
What you’re asking the Original Poster to do is take the most potent, quickest-rendering, most accurate form of lighting (which is that huge fireball in the sky, if you’ve forgotten what we’re talking about) and NOT use it. You’re asking the OP to perform piles of test-renders hoping to achieve “artisticness” or something. You’re implying that using the sun for lighting is wrong, and that PortalLights aren’t the best way to optimize the sun/sky for interior rendering.
Try telling that to this guy:

Also, if you’ve ever looked at a clear sky, you would know it’s a gradient. Any HDRI involving the sky also has gradients, albeit multidirectional obviously. Sure, some clouds for details are sweet, but you can control the atmospheric gradient in the sun/sky far, far easier than tweaking an HDRI in a separate application. And you can also add clouds just fine to the sun/sky.
But hey, go ahead and toy with all your random little lights and do dozens or hundreds of test renders per project. I’ll be long finished and have already signed the client; see you when you need to borrow some money, LowJack.