Zufari is probably the best example of how bad planning can ruin several aspects of what should be a decent attraction... The pre show that got binned after a season, the awful loading area and the finale didn't add anything worthwhile to what should've been a simple safari experience... It needed a story like one needs a hole in the head, especially one seemingly forgotten about halfway through...
Zufari sums up Merlin's style over substance quite well, lots of good ideas, but the implementation is often left wanting... Which means that the additions never tend to go beyond 'good', maybe bordering on 'great', but never further than that... Swarm itself has some questionable design choices (the roofless station removes any potential atmosphere as an example), and similar arguments can be drawn against all their additions...