You do not decide what is important to put in Fallout. Bethesda does because they spent millions to acquire the franchise and gain that right. Their decisions are either successful or not depending on the market response. As Pete Hines said after Skyrim's success as well as the successive triumphs of each of the previous games from Todd Howard's team starting with Morrowind, Todd has earned the right to do whatever he damn well please. When you show similar success, your viewpoint might carry some weight.
As for important features, they showed every important feature that was feasible for a 30 minute E3 presentation. Some features such as customizable jukeboxes didn't get shown due to the venue but have been mentioned in subsequent interviews. Features such as the crafting/rebuilding/settlement systems are optional but absolutely critical for a Fallout game. As was pointed out in interviews after the presentation, Elder Scrolls might not need such a system and it would be tricky to introduce it into Tamriel, but Fallout is perfect for such a system because the game includes humanity's attempts to recover & rebuild so such a system actually allows the player to role play a character who is actively involved in such a process rather than being force fed what the developers choose.
Sims has nothing to do with Fallout and has never been mentioned by Todd as a source of inspiration for the team, at least not in the many interviews with him that I have followed over the years since Morrowind. It is unlikely that his team used Sims as an inspiration for character creation. I have stated in several posts the problems with BGS' character aesthetics and their refusal to offer choices for certain styles from East Asian entertainment that have proven to have global popularity, including modders introducing such styles into BGS' games. This problem is coupled with the continuing marketing claims by Todd and Pete of "be any character you want and do anything you want" which is patently untrue due to their forced/limited/unappealing character aesthetics. However, it's a very different problem than claiming that FO4 is somehow inspired by Sims. The visual style of FO4 is far closer to a franchise like Borderlands and that franchise is far more likely to have been an inspiration, although it also has not been mentioned as a source of inspiration, again to my knowledge.
The dog is included due to the original games. It is also likely a focus because Todd is apparently a dog owner/person based on pictures of him I have seen in his casual time at home away from work. It's likely that some other people on the team are also fond of dogs. I don't care for dogs and would like a cat/feline of some kind, but I'll simply ignore the dog as an uninteresting choice for companion. Actually, BGS' choices for companions are never of much interest to me so I use mods to allow me to recruit/create companions who actually are interesting to me and fun to team up with. You can do the same thing, as can anyone else who doesn't want the dog.
The choice of dialogue wheel and related features is likely due to the fact that other major action-RPG hybrid products of the past several years have used similar features.
Why spend time and resources on these features? Because in many instances, they are fundamental aspects of a Fallout game regardless of your personal preferences (or mine, for that matter). Far more important, though, is the simple fact that Bethesda is a game COMPANY which means that they are in business to sell as many products and make as much profit as possible. What determines this outcome? The market, nothing else. The market has shown that people want many of these features. Of course, the market has also shown a demand for far better choices for character aesthetics and certain other elements, but BGS has the choice to refuse to pay attention to certain market demands while answering others. They paid millions of that right and we haven't. So far, the market results have been extremely favorable for them, so Todd and his team have been granted the authority to do pretty much whatever they damn well please.