I listened to podcast by sim settlements creator and he had lead for F4NV so i have some details:
- It is not just FNV with better graphics. Prime motivation for F4NV is to bring good changes from F4 into NV like much much much better gunplay or weapon mod system, power armor, improved ferals but at the same time take from FNV what was great about it like DT system, different ammos etc. Hardcore system from FNV will be replaced with Survivor and naturally world space will have to acknowledge that (like adding beds for save). The core is to have FNV gameplay with benefits of F4 improvements to gun plays and stuff rather than having F4 gameplay in FNV. Settlement system is not core of game and will be released as an option as they say it doesn't fit well with FNV theme.
- Gameplay system wise most of the hard stuff is already done. Like XDI which brings back more than 4 menu options for dialog, skillupmenu which brings back skills and nv like menu. Most of those changes are straight up engine changes so they are not buggy nor they cause problems long therm and don't feel like they are bandaid. Currently the biggest problem for them they are working on is creature behavior system. F4 has no behavior system to mod so you can't effectively make creatures other than just coming straight at you. They are currently reverse engineering that and progress looks good (mainly this is about securitrons which have wide tasks in game) this is the biggest hurdle for them.
- Around 150 people working on project right now including voice actors including actual people who work in game industry right now as level designers, programmers etc. This is more pro than pretty much any mod out there.
- Show don't tell approach. They don't want feature creep so they will be only releasing progress when they finish some feature or milestone. No "this is feature we are working on but it might change in future". This is why they show finalized parts of game like skill system, opening sequence etc and not work in progress.
- Finish module = release. Everything they will do they will be release for people to play with. They already did that with their frameworks like extended dialog system or skillupmenu, DT as well as assets as you can download already some of the guns and armors from nexus. While it will take a while for whole mod to release they don't want to work on something and then something happens and everyone multi-year work is down in toilet. They have contingency plans for their work so if they will not be able to continue they will be releasing what they have and this is also reason why they go for achievable goals that can be released first rather than take 100 different things and each of them in various forms of completion. So before release of NV you will see most of their work like guns, armors, props etc being brought into F4. The stuff they make models for etc for now are stuff that can be brought into Fallout 4 so modders can see their work being done and don't get burned out of project like other big mods out there.
- Around 80% of NV wasteland is "touched" rest 20% is height-map. Rather like most of big project going hard on landscape to hype people up and then realizing they have issues with gameplay/ai/monsters/etc that kills their project and can't continue they want to sort out every problem first and then go into full production as landscape has least issues to deal with. As for landscape itself it will not be 1=1 version. First of all F4 engine had some serious rework on what is allowed in it when it comes to size of cells and so on and they want to take advantage of that. For example Freeside in NV is a mess. It is way to sparse and could use up some tightening and freeside shouldn't be split. So in this case they will change it to be smaller. On other hand true desert areas in NV are really small and they plan to expand them so they actually feel like deserts rather than sandbox for kids.
- It will not be compatible with fallout 4 world space. NV will not be a new place you can visit but you start NV when you click new game with new main menu UI for F4NV. They say that there are simply to many changes to internals of F4 systems to even try to get both working at the same time and F4 worldspace quests etc will be just broken. Though they say that some autist maybe will be able to do that but this is not their focus and they don't plan TTW like integration.
- They will be not using NV voices because of Beth didn't gave them ok as US union for those actors created some insane stuff that severely limits reuse of voice even in fan modifications. For now voice work is their SECONDARY goal. The most important part is to remake game. So if they will finish doing that but they still don't have all voices recorded they will release it without those voices and slowly update over time with new voices. Obviously there is nothing stopping someone writing some scripts to extract voice from FNV and change new voice acting for old but they won't do it. The crux of licensing problems is in extraction of files from their archives. TTW gets around that by not actually extracting any voice files while you need to do that for F4 as NV format is different than in F4. What is more weird is that they have original FNV voice actors who want to reprise their role for F4NV for free and they can't use them either as Betsheda can't fuck with union. All in all they have to record around 15 000 lines and they know this will for sure take longer than creating game itself. They have effectively two teams working. One on game and other one on voice acting and both of them are almost completely separate from each other.
- It will require for player to have copy of FNV installed but it won't take anything from that copy. It is license requirement they made with Bethesda.
- They focus on vanilla game so no story DLCs. DLC will be done after vanilla if they will have strength at that point to continue. Though they will be bringing some of DLC stuff into base game like some weapons, perks etc. Gunrunners and various stashes (pre order packs) will be in base game and they will suggest themselves on that with JESawyer mod (integration)