Quote - Didn't say I know any render engine ;)

You didn't, but then Vue is probably the most used app here after Poser and DAZ Studio...
My point being that many (most) users know what to expect when they hear "sun"-light.

Quote - We have to do with several "know-how levels", especial with Poser. So a "full automatic" is a really good thing.

"Automatic" looks good on paper, but it usually is too sophisticated for the base users, and too limited for the advanced ones. Meaning you get flak from both sides.
I'm a partisan of making a somewhat advanced GUI, which might cause some comprehension problems to newbies at the start, but since being a newbie isn't a career, but just a temporary status, they will eventually be happy the exporter doesn't limit them to their original noob-ness.

Or, to be less consensual, if somebody wants to use an external renderer, he has to prove he is capable of taking 30 minutes to read through the Lux documentation. If he doesn't, well...

Quote - This is why I say anything with a prefix in his name should be left alone or handled in a special way. At the end it would hurt nobody.

No, I don't agree with this way of doing things. You shouldn't need to create fake named materials (complicated!) or lights; It's only once inside the exporter you should be asked to decide what to keep, what to reject, and what to transform into whatever Lux-ish.

Ideally, I load a 2-years-old scene, I hit "export" and it's at this point that the exporter allows me to manage the export to Lux, including material translation ("that's what I suggest, do you want to tweak it/use something else?"), light creation("Those lights found, what do I change them to? Any materials I need to lightify?"), and of course the classic setting already covered by the experimental GUI BagginsBill released last week.