WARNING: The following contains spoilers for the Boruto manga.
Naruto has worked assiduously since the Fourth Great Shinobi World War ended to bring about a new era of peace. He's made the alliance between Konoha and all the other major ninja villages official, encouraging everyone to use science and tech as a way to make life even better. It's changed the way even old-school ninja like Sasuke see the world, illustrating how Naruto is living up to his word to be a Hokage his dad, Minato, and other predecessors could be proud of.
However, as the Boruto anime and manga unfold, we're seeing that Naruto and the Nine-Tails inside him, Kurama, haven't fixed their biggest problem: succession.
In the Naruto series, it took a while for Kurama to accept Naruto when Minato and Kushina bonded the beast to the kid before they died. He felt mistreated, like a mere weapon, after the likes of Madara and Hashirma objectified him but eventually, he realized Naruto was pure of heart; someone who considered him a sibling. Since then, they've worked in unison, sharing chakra to battle several opponents over the years, such as the Akatsuki and Kaguya's extraterrestrial clan.
But with speculation pointing to the hero dying as he tries to stop Isshiki in the manga, we have to wonder what the plan is for Kurama. There should have been something in place so that Naruto doesn't come off as reactive. This lack of proactivity doomed the village already when Obito -- manipulated by Madara -- unleashed the beast, and if it falls into the wrong hands again, it could spell a major disaster. If Naruto's dead, it'll be even worse, as we're not sure Sasuke can take the beast on alone, especially as we don't know who could host, tame or corrupt it.
Remember, when Rin died, Isobu (the Three-Tails) moved on and was revived, so Naruto's passing could see Kurama weaponized by another villain. Orochimaru is one candidate because while he's been somewhat heroic lately, he's also worked with the Hashirama Cell, which could control it. If someone also takes ahold of Yamato (who has Hashirama's DNA), they too could turn Kurama evil, and we can't forget that if someone copies the Sharingan, they can make Kurama their fox of war. We can only hope if this ever happens, they're not on the power levels of Madara, Kaguya or Isshiki.
Naruto really should have used science to figure the future out. He can loan chakra to his son and other soldiers, and we've seen Kurama can manifest to Kawaki due to their chakra connection in the manga. Naruto can split pieces off to Boruto and Himawari as markers, setting them up as hosts when the time's right.
After so many years have passed, one would expect Naruto to have had a team studying the centuries-worth of scrolls on this topic. We get that he has day-to-day missions and governance to tend to but this is an important project his scientists have dropped the ball on. Kurama's also a family member so not only would Naruto be keeping him safe, but he'd also be protecting all the lands, something that's part of his bloodline and overall legacy as a leader.
Training his children for this would have also made him a better father and inspired them, even more, to live up to his name when he's no longer alive... which might be sooner than they think.