This is an interesting question, because the first thought is to explain it to you a terms of programming methodology. But your question is about the language used in the statement:
The point here is you want to be as specific as it makes sense to be every chance you get.
Let me give some context of my own, first:
Cascading Style Sheets allow you to define styles in a hierarchical manner, relying on the higher levels to define a set of styles that apply to a broad range of rendered elements. For instance, you may specify overall font styles, including font type, font color, and font height, as examples.
At the lower levels in the style sheet definitions, you may modify the styles for more specific elements. So you may want to change the font weight for an element, to emphasize a word, for example.
What your sentence is telling you is that you do not need to respecify all of the other details. Only specify the style element that is needed. This is what would make sense. This is all that is necessary. To do otherwise would (or may) create additional work, it would be unnecessary (obviously), and may even lead to other unexpected problems. To specify elements that have been adequately defined at the higher level would not make sense. There is no reason to specify style elements that are already specified the way you want them to be. (But you should respecify those that need to be changed.)
So to make sense in this case means to be reasonable or logical.
The point being made is that you should only be as specific as it reasonable (or logical) to be. Do this every chance you get.
In Australia, we would definitely say
The passport will expire in 2 years.
as though time followed years, and in is understood to mean about or approximately.
It is with some surprise that I read the comments from esteemed users @Janus and @Edwin, hence my qualification in Australia - perhaps this is regional usage.
Best Answer
option 1 is correct, regarding both of your questions.
a) If you wanted to say "will
<something> to be" you'd say "continue" rather than "remain". In other words, you can say "will remain as one of the..." or "will continue to be one of the", but don't mix them up. These two alternatives mean the same thing in this context and both are commonly used.b) Saying "would" instead of "will" makes it hypothetical which isn't what you want to do: you're making a prediction about the real situation, not a hypothetical one.
You'd use "would" in a situation like "If there is a large change to interest rates in 2017 then cost reduction would continue to be...". Here you're talking about a hypothetical situation (interest rates increasing) AND you're implying that if that situation doesn't come about then cost reduction might not remain as one of the key priorities.