That Fallout 4 could have been toned down to get a USK18 in germany, is indeed a silly idea. We saw the videos of the combat system and it looked bloody enough. So exploding bodies, etc. are still in. Yust that they are allowed in the german version aswell.
Ok, admitted. I am happy for a uncut version not because of the whole blood thing, more that it won't be mutilated like Fallout 3 and Fallout: New Vegas.
1. I remember, that enemies where way stronger in the german version, because you hasn't been able to cripple them. I used a blood patch and noticed it immediately. Without, the deadclaws where extremly dangerous. They where running for you and attacking in full strength, until they where dead. With blood patch, you crippled the legs and they where way slower and if you shoot the arms, they where weaker aswell. Or you shoot the heat and they where gone. By more as one, it was really a problem.
2. The NVSE. The international version wasn't working for the german version. Okay, there had been a german version of it aswell, but normaly way behind the version of the international one and not supported so well. Using larger mods was a problem. Especially, if they need the NVSE. A lot of them haven't worked at all.
The blood patch was a bit of a relief, but i had to update the patch, all time a patch came out. Aswell the game was incredible instable then, crashing all time. So not to much fun. After the Ultimate version was released completly uncensored, i even bought the game a second time (as it was reduced). It changed everything. Everything was working fine then and without problems.
Thats the real reason i am very happy, to get a uncut version of Fallout 4 now. No balancing problems and tools like the script extender and the mods would work without problems. 
So, to explain how the rating, censoring etc. system in germany works (I actually have read a bit into it again, to have it in mind again, how it really works):
USK: The USK wont go active, without the publisher sending a copy of it in. Then the game is tested and if it isn't to extreme (extreme glorifying violence, violence as the main part of the game, or hazardous for the development of somebody, illegal content [see swastika]), then it gets a USK approval. If the USK won't give the game a approval, the BPjM takes over. Not automaticly, but its very common, that some instance would send it to the BPjM then. When the game gets a USK approval, it normaly can't be indexed anymore.
The USK isn't doing the cuts aswell. They are telling, why a game can't pass the test and the publisher can send a censored version in, for a better aproval. Often, the german version was even censored by the developer before send the game in. So the USK haven't even seen the uncut version. If i remember correctly, Fallout 3 and Fallout: New Vegas was even censored before send to the USK. Could of course be wrong, but it was at least by NW the case. Then the Ultimate version was send in as uncut version and got to their surprise aswell a USK18.
One of the reason, that Bethesda has become brave with sending uncut versions in (The Evil Within, Fallout 4). And how it seems, they are very successful. Ok, we still have to wait for Doom. 
BPjM: The BPjM is the organisation who is responsible for indexing the game. The BPjM can go active in many cases. The USK can call it, but it can be called by other organisations aswell. In fact, the BPjM would go active, even when the publisher won't send it in. So a extreme game, not going to the USK, would still go to the BPjM most likely. The BPjM is checking the game by themselfs. Then they can index the game, or refuse the indexing, when they don't think, its to extreme. Such a game is automaticly cleared to get a USK approval then. Even when the USK refused it first time. So it can be send to the USK (again) and will automaticly get a USK18.
Having a USK approval means, you can make advertising for the game, aswell in TV (independent from the accepted age) and the retail version can be displayed in the stores.
If a game fails the BPjM check, it will be indexed and there are 2 lists. List A and List B:
List A: Is the most used list and means, that the game can't be advertised (even a test in a magazine applies as advertising, even when the test is horrible), it can't be displayed open. Its allowed to sell the game, by asking directly for the game and the buyer is an advlt. Happens rarely, because people looking for the game would most likely buy it on Amazon as PEGI version, and not in a store. So the game is normaly not sold in shops.
List B: Here we are going in the more criminal area. It is still allowed to buy the game, but its not allowed to sell it in germany. Thats very common in germany, that you aren't allowed to distribute, but allowed to buy something. You can buy the game, but because its officially not allowed to sell it to you, the customs can retain it.
Well, nothing Bethesda has to care for by Fallout 4. And i am very confident, that the TV advertising will start very soon. 
BTW. If somebody want to know, why Mortal Kombat X wasn't indexed:
Mortal Kombat X was send to the BPjM. They refused the indexing, then the game came to the USK and got its 18 approval. The game hasn't even been by the USK before, because Warner tought, they won't get it without indexing one way or another. Of course they sended it to the USK after they heard from the non indexing, to get their USk18.
So why hasn't it been index? The answer is: It was to brutal. Yes, the high brutality factor was to unrealistic for indexing. Thats the official statement from the BPjM. Because of this, the game is now with USK18. So the chances for Doom aren't as bad, if Bethesda makes it brutal enough. 
Aswell, one one official statement for the more and more brutal games who got through the BPjM is, that because the technology advance more and more and the graphics is more and more realistic, it let's less room for speculation and you can't associate it with the reality so well anymore.
(Source: https://translate.google.de/translate?hl=de&sl=de&tl=en&u=http%3A%2F%2Fwww.gamestar.de%2Fspiele%2Fmortal-kombat-x%2Fartikel%2Fmortal_kombat_x%2C51150%2C3234010.html)