I kind of like the approach they took with the mess hall interior, or at least don't mind it.
The Jungle Cruise and the Adventureland Verandah were features of the original 1970s Magic Kingdom, and both reflect a certain level of 1970s design. All of 1970s Magic Kingdom, especially the restaurants, had a more simple, minimalist approach when it opened - Fantasyland (especially when you compare it to New Fantasyland or in places like Paris), the original 1970s Tomorrowland, interiors of shops in Liberty Square, so on.
Meanwhile, the cluttery, "stuff on the walls" theming approach didn't really happen until the late 80s/90s. You saw this in attractions like Adventurer's Club, Animal Kingdom, Tower of Terror, etc. Some would say this style is superior, but I think there is charm in both.
In my opinion, the original Adventureland Verandah was one of the most beautiful examples of that earlier style of theming. The theme didn't come from all the props on the wall, but more the colors and feel of the architecture. I'm glad Disney decided to preserve that idea with the new restaurant (and even continue the original restaurant's motifs in the new bathrooms with the ornate tiling). I think if they were building a new Jungle Cruise restaurant from scratch, I would feel differently. But because they were renovating the already-existing Verandah, I'm glad they decided to keep the original design style, and only added a few props here and there to get the new theme across.
In other words: if they decided to renovate Columbia Harbour House or Crystal Palace into some new restaurant concept, I would hope they wouldn't just completely cover the walls with props and crap to reflect the new theme.