It'd be remembered for having the first Sixth, but the general populace of Sentai fanpeople wouldn't really think about it much.
I strongly disagree. Zyuranger was a hugely ground-breaking series is one way I haven't seen anyone mention yet. Zyuranger is literally the first time that Sentai is produced as a fantasy series, on top of all of its other innovations. Turboranger included some fantasy elements, but still strove to include a lot of the sci-fi tropes that defined Sentai in the 70s and 80s.
Zyuranger goes all-in. It's the first Sentai series where everything is fundamentally magical. The robots aren't robots at all, or even magic robots, they're
literally gods. And they're gods in a fantasy RPG sense, who speak regularly to the heroes, either offering counsel or chiding them for bad behavior.
Likewise, the Zyuranger heroes aren't just people with superpowers of some sort, they're literally the nobility of a lost fantastic age. They have to go on a heroic quest to gain the Legendary Weapons, and they fight an evil witch who's surrounded by creatures from myth, legend, and literature.
After Zyuranger, magic and fantasy elements play an increasingly large role in the Super Sentai series. Once you get into the 2000s, sci-fi shows actually become a rarity, while magical-themed shows like Gaoranger, Magiranger, and Shinkenger are the norm.
I think it's easy to view Zyuranger dismissively, because we now take what it added to Super Sentai for granted. Zyuranger was the series that rather decisively got Sentai out of the rut it'd fallen into toward the latter half of the 80s. The post-Live, pre-Zyu shows were (mostly) still good, but they were increasingly derivative. Zyuranger was something completely wild, fresh, and different (if also unpolished and a bit incoherent).
Timing should also be considered when talking about Zyuranger's success. The Jurassic Park connection has been made before, but it's also worth noting that Zyuranger is produced right as the 16-big console RPG boom is taking off in Japan. Literally everyone, from kids to grandparents, were playing games like Dragon Quest, SaGa, Final Fantasy, Megami Tensei, Tales, etc.
Seeing those themes in Sentai, with the heroes as a questing party and the robot approached as a "summoned diety," was probably really appealing to viewers at the time. I find this aspect of Zyuranger is also harder for Westerners to appreciate, since console RPGs never became a mainstream genre over here until the release of FFVII (which actually marked the beginning of the first boom's end in Japan).