It's only limiting for those with limited ideas

But for the mega hdr stuff, the super florescent hdr doesn't really make sense unless the room is hazy or something like that. So it looks kinda... out-of-place to me. But if you guys really want to get this mod to completion, get a basic version of everything made first, so then you have somthing completed, then go back through and add in all your fancy things you have planned.
Meaning get a basic mock-up of the mod made, with only basic structures and textures so you can optimize the pathing, and pacing of the mod first. Then once everything feels right, add in all the detail stuff like great lighting, good textures, effects, etc.
Otherwise you will spend forever on one section of the mod, and make it super amazing. but its disjointed from the rest of the mod, and kinda tarnishes all the hard work you put into it. Or you do all this work and find you have to re-do a big portion of it because you decide to change how something plays.
If you do this it will give your mod a much more complete feeling as a single story when it is all done, and it wont feel like a bunch of maps that were piled together.
That and it will give you a good idea of how much time certain aspects will take.
So start basic at first, then build up from there. A building is only as strong as it's foundation.