What would be the purpose of opening Pages, Numbers or any other application if you don't want to work with it? Do you just want to take up memory and CPU?
Let's tone it down OK? I think if you had explained your question with more clarity you would have received a different answer. Member MacinWin was merely trying to respond to a question that quite frankly made no sense the way it was asked.
raredesign, let's try to get back to a better start. What I was trying to say was that starting an application like Pages with no document accomplishes almost nothing. The app comes into memory and uses CPU cycles with no productivity. In older, slower machines, if they had enough memory, it may have made sense to do that if quick response is critical and the load times are slow, but with modern equipment and operating system features, it's kind of pointless to have all those applications idling. But if that's what you want, you can have an idling Pages by letting it open a New document, then picking a blank page format and immediately closing that document without save. That will leave you with a running Pages with no document. But if you want to do anything, you'll need to open a document. The same process will work with Numbers, but again, if you want to DO anything, you'll need to open a document in which to do it, whether you save it or not.
If the objective is to have Pages/Numbers/Textedit/Whatever in the dock, handy to open, you can just put it there without it being open, consuming memory or CPU. Then you can just click on the dock to open the application (and a document in which to work), do what you want and then minimize back to the dock or shut down the application, in which the dock still holds the icon for you to restart it whenever you need it. I can't read the mind of Apple engineers, and they've certainly done some really stupid things on occasion, IMHO, but I think what they were trying to accomplish here was to expedite the process for the 99% of us who only open an application when we want to work in it and so we need a document in which to work.
It's probably possible to write a script to do the opening/selecting/closing steps using Automator if the choosing is cumbersome to you. I don't know how to do that, however.
EDIT: I just looked at the Preferences for Pages and you can set it to skip the "Template Chooser" if you set a default template for New documents. IF you do that, then you only have one click to get to a new document and two clicks to close it. And again, it probably could be automated if you want.