Nah Smash 4 had no 'personality'.
Smash 64 had the lore of toys fighting to escape the master (hand) with it having comic book imagery (box art, the entire intro, classic mode clear pictures)
Melee, admitedly, had no personality by itself but the adventure mode and increase in stage count made it the first smash to properly look like a Nintendo All-Star crossover.
Brawl had the Subspace and everything seeming "epic finale" from the music, the atmosphere, to the content it offered.
Ultimate is a tribute to the entire series and continues the lore they abandoned after Brawl.
Smash 4 recycled too much from Brawl whilst getting rid of the finer details that made it feel special. Smash 4 was essentially "yeah this is the series you like. Here's more stuff but also less stuff". It felt more like a routine rather than something made to stand out unlike past titles.
Ultimate started with a bang with the everyone is here to including fan favourites. Then it made two modes (Spirits and WoL) that try to mingle non-present characters into the mix whilst obviously showing tons of love doing so.
Smash 4 was a fun game but yeah, it didn't have "personality" as you put it. At least to me.
Even Smash 4's theme is kind of dull and lifeless compared to all the others.
64 had a theme that incorporated the different series involved with a sense of whimsy that went with the toy theme.
Melee had an epic theme that makes it seem more grandiose. Instead of it being a bunch of toys fighting, it's a huge showdown with all these different characters.
Brawl had its amazing orchestra with Latin lyrics about great heroes and rivals banding together to save the world.
Smash 4... has I have no idea. The theme isn't nearly as dynamic or interesting as any of the others. The trumpets sound flaccid, and overall it doesn't inspire any intense emotions. It's not bad, but it doesn't get me pumped the way any of the others do.
Ultimate has a really powerful theme that communicates how all the characters are here, and then has a different remix with amazing lyrics that accompanies the story and scope of World of Light/Spirits.
While Smash 4 was helpful for us getting to Ultimate, it definitely doesn't have much of a lasting impact outside of its core gameplay.