I do agree that Park was underutilized, like everyone else, but especially Hoshi, Travis, and Malcolm. I'm not on board with those who feel that Travis should've been killed off. What purpose would that have served? Especially since he was already underutilized anyway. It reminds me of a similar story in Discovery's second season, though that fated character got even less focus than Travis, Hoshi, or Malcolm.
Travis's plight reminds me of a bit of Harry from Voyager. They didn't know what to do with him and largely kept him in place. The Boomer concept wasn't explored enough, and I think when they put T'Pol on the ship she undercut the use of both Hoshi and Travis. What good is Boomer know-how when T'Pol can just go to her trusty Vulcan information? And while they did find someways to use Hoshi's abilities with language I felt they could've gone further if they didn't have T'Pol, and the information she already had there.
I liked T'Pol, but was just thinking if her role had been rethought to carve out more space for Hoshi and Travis we could've gotten more of an ensemble series. But as others have already suggested, ENT was seeking to emulate the TOS approach and IMO failed to grasp that contemporary audiences were more on board with ensemble series, especially since TNG, DS9, and VOY were all more ensembles. I also would've been okay with there not being a Vulcan character on ENT either. Casting Blalock as a human character would've worked for me. I think ENT could've stood out if it had been an all human cast, or maybe just had Phlox as the only alien onboard.
Also, I thought Hoshi and Travis had nice chemistry and the opportunity to have them in a relationship was missed, or even a triangle among Travis, Hoshi, and Malcolm.