I swear I must be the only person ever who thought the vanilla interface was just fine. All I ever cared a lick about was getting a bigger map and having the HUD display less prominent. I ended up having to deal with most of DarN in order to get what I wanted and frankly I think it goes a bit too far on the whole smaller print thing. I still ended up with a hybrid of Immersive Interface, Darn, and hackish methods to force the menu fonts back into a readable size.
I'm kind of in the same boat, to a certain degree; I never saw a need for any major overhaul. I installed BTMod then Immersive Interface to make the HUD more compact and smaller, installed the MiniMap mod and did a quick xml edit to make it work with what Immersive Interface had done, and that was about it. I've got a nice big customized map I can zoom in and out of too (Map Marker Overhaul and Dynamic Map). Everything else has been minor tweaks, like doing xml edits to make the descriptive text show up in the center when focused on an item, which I might have copied from DarN actually (and which caused shadeMe's mod named after Vacuity to not work right for me). Oh, and my totally lazy modifications to make the text in menus a lot smaller, making a custom sized font and editing the xml files. I didn't quite do everything I needed to, as you can see with some of the quirks in http://img268.imageshack.us/img268/8071/arrowmenu1.jpg http://img813.imageshack.us/img813/1262/arrowmenu2.jpg. I should probably fix it at some point but I've since forgotten the details of the xml files so I'm being lazy about it, hehe.
I can totally see other people wanting to majorly overhaul the interface, but I've basically been able to get it exactlywhere I want it through tweaks here and there. Actually I probably took the more difficult route, but I guess there's a certain satisfaction being able to tweak each specific component to your exact preferences manually. But for now the closest I'm getting to using DarN is seeing the same red background texture it uses in menus while using Atmospheric Loading Screens, heh.