Don't worry for your English. I'm French... [;)]

the first one is the "smooth" function for the models (the same function present in blender when you select one or all the elements)

Could you give more details about what this feature is supposed to do? I used Blender a little and don't remember using this feature.

the second one the possibility exportation for luxblend with the scene, the camera and the lights as created in sweethome

If I add a new export format, I would prefer to export to Collada/DAE format since Sweet Home 3D supports this format at importation time and Collada is an open format that I already learnt. But the community could also write some export plugins inspiring themselves from OBJWriter class and Copy as new furniture source code.

possibility of a variable focal lenght of the camera

This feature already exists for the virtual visitor camera. It's in the 3D view modification dialog.