This is a difficult part of Swedish grammar surrounding gender. When you talk about a general concept or abstract idea, predicate adjectives are in the neuter even if the noun is not.
As an example:
Mjölk är gott - "Milk is good", but Mjölken är god - "The milk is good".
In the second, you are talking about a specific instance or unit of milk, but in the first you are talking about the general concept of milk, not a particular unit of milk.
You can also see this with languages.
Svenska är svårt. Din svenska är dålig. (Used because "bra" doesn't decline ;)
This rule does not apply to attributive adjectives, so always "viktig kommunikation", never "viktigt kommunikation".
Thank you for the explanation. Just to clarify on what you mean by "general concept or abstract idea": do you simply mean whether there is an article (definite or indefinite) or not? Or is there more to it than this?
It definitely has a semantic component to it, you never use the neuter when referring to human by name, for example. Plural nouns also not subject to this rule.
Aha! Thank you for clarifying! So just to make sure I'm understanding correctly:
Kommunikation är fint.
Spiffwalker är fin.
Vin är fint.
Viner är fina.
Sound about right?
I can't think of any situation where either sentence would fit better. Would have exactly the same meaning and equally used I'd say