LinkedIn forces that kind of specific responses, and it's disastrous. Not only does it result in very little useful information, but the forced response format often compels the client to misrepresent the nature of the project because the format of the field or the available responses don't fit.
Many of my clients don't know or care how many words a piece will include--they're looking to me as a professional to determine what it takes to achieve their goal. I also wouldn't want to force them to create a deadline when most are flexible on that, or to guess at what their maximum budget is when they probably don't have enough information to determine that authoritatively, and most clients turn out to be willing to pay more than they anticipated once they understand what they're getting.
I would also hate to standardize postings in that manner because I learn a lot about a client and whether or not we're likely to be a good fit by the amount and nature of information he/she provides, the facility with language in the posting, even the way the posting is laid out. It would be much more difficult to assess potential clients if we forced them all to act the same.