"The coffee here is delicious."
The difference is the context. In the curry example, you're bringing up the curry as a topic (は) that can span multiple sentences after that. However, in the coffee example, the place is the topic that spans multiple sentences and the coffee is the subject (が) of that specific sentence only.
The wa particle is specifying the topic, and can be translated as "As for...." or "Speaking of....". The ga introduces the new information and is sort of like the focus of the sentence. As for here, THE COFFEE is delicious. The word before the ga answers a question, spoken or unspoken. What is delicious here? The coffee is delicious here. Sometimes the topic and subject are the same which makes things easy.
Really, the only thing a Japanese sentence needs to be correct is a predicate (verb or adjective) that comes at the end of the sentence (which may or may not be followed by politeness markers, tone/emphasis markers, other particles and whatnot such as desu, da, ne, yo, kara, etc.). Everything before the predicate can be in any order because particles tell you how the words relate to each other. Some patterns are more common than others, though. So there really is no reason that the wa particle is before the ga particle other than that is the more common way of saying it and seems to be easier to understand from an English point of view.
That's my understanding of it anyway.
Why is コーヒーはここがおいしいです wrong? That isn't saying the place is delicious, is it? What if the people are talking about coffee, and the place is only the subject? Without further context it is impossible to determine if the conversation's topic is coffee or the place the coffee comes from.