To be fair, they started as newcomers at some point.
Of course they did, but I'm talking about what would be the more interesting story to tell about them. No cinematic attempt to depict them as newcomers has worked, and I think that suggests that the beginning of their story is not the interesting part. What matters most about them isn't their power to stretch or turn invisible or burn stuff, but the power of their reputation and influence and leadership. So I think all this filmic fixation on how they started out is focusing on the weakest part of their story.
Heck, I think the Tim Story movies actually did a decent job portraying their fame and influence -- not a great job, but a decent one. And they reached that status pretty quickly in that universe. But those movies still missed out on a lot of the depth and history that informs the comics characters, particularly Sue. The comics' Sue has grown immensely from the feeble, submissive helpmeet Lee and Kirby created into the renowned leader and diplomat and unstoppable badass and mother of godlike mutants that she is today, but the movie versions tend to be closer to the weaker version of the character.
My suggestion would have to be this, if they get the rights back to Fantastic Four: Bring in Reed Richards, established scientist first. Then spin them off and give them their powers. Powers are an established thing, so don't have them waste time shocked or distraught by having them (except Ben, whose complaint is the transformation of his appearance, not that he has powers). Then make them expert consultants/heroes/scientists/explorers (basically, what they were before, but with powers).
Which is doable, but as I keep saying, having them be new
at all would still deprive them of the most interesting aspects of them in the comics. There's just no way to reconcile that. I'd rather have them stay in a separate universe and start out with them as a well-established institution than sacrifice all the parts I like in order to shoehorn them into the MCU.
Heck, maybe that's what Fox could do to salvage the current series. Bring in a totally new creative team, keep the cast (maybe), but pick up maybe 5 years after their origin, make zero mention of those events, and just focus on what they've built since then. Be agnostic about whether this year's film happened at all and just tell a new story about the FF later in their career, one that builds on all the best aspects of them -- their institutional status, their role as explorers and adventurers rather than just crimefighters -- in a way this year's film failed to do. That separation in time would not only let them focus on the more mature team that I'd like to see, but would help distance and insulate the sequel from its predecessor. Kind of like how
The Wrath of Khan was set more than a decade after ST:TMP and made no mention of its events (although I personally think ST:TMP is the far better movie of the two).
Although, of course, that approach would require its own sacrifices, because you'd lose the FF's connections to other superheroes, their anchoring role in that community. So either way, I guess, it would be a tradeoff.
Maybe it would be possible to bring the FF into the MCU and build them up into an establishment presence over the course of a few movies and a few years, like the way the Avengers have been built up over the past few years to where they are today. It could even be part of a long-term strategy to shift the focus away from the Avengers as Downey and the other stars eventually move on, with the FF gradually taking their place as the anchor of the universe. But it would take a while to get there, and I'm just not interested in seeing another take on them as newcomers.