I think it's a question of "coherence" vs. "association". Things can be coherent in a number of ways. They can be visually coherent, emotionally coherent, logically coherent, musically / auditorily coherent, etc. But the idea of coherence is a sort of synergistic effect where everything works together towards one goal. One thing builds upon another upon another in a cumulative way.
Whereas associative and categorical thinking is more a matter of "This made me think of this, which made me think of this other thing, which made me think of this other thing over here." I don't think that's necessarily a bad thing, in terms of theming. Many of the lands at MK are probably built more around it. Frontier Land is a collection of things we associate with the American Frontier, Tomorrow Land is a collection of things we associate with "the future", and so on.
Lion King is associated with Africa, yes. Is it visually coherent with Harambe? Emotionally an extension of what's happening at Harambe? Not necessarily, and my sense is that AK has been built more around "coherence" vs. categorical theming. I can see why people are resistant to changing what is probably the most cohesive of all the parks (especially as people have watched Epcot and HS become sort of "hodge podge" kinda parks.)