They are like fingerprints; no two are alike, even within the same organization. One further point, opinions about what makes a good finished product are like noses_everybody has one. The ones that work and prove to be executable are the best. With this in mind, let me offer my views about business plans at a macro level having written a sizeable number of plans for internal and external applications. One other point, a business plan can build a team quicker than any formal team building activity.
Any casual viewer of the BBC programme, Dragons Den will be aware of how easy it is for weaknesses or gaps to be identified. Depending upon the purpose of the plan, this may, or may not, prove to be critical. It is often easier to recognise such weaknesses and gaps, and be prepared to deal with them, either by noting them in the plan itself, or having appropriate answers available should the need arise.