I've been trying to set a standard for entities so that we can get them all done over the next few weeks. I thought originally that just having a page specific to the entity was best, but a lot of people seem to prefer to have general information about the actual thing the entity represents in game on the same page, so I have combined the monster and monster entity information on the same page now. This information is still quite basic and volunteers are needed to increase the amount of information and improve its quality.
For things that don't have recogniseable in-game thing, such as triggers and lights, I'm not sure how to organise the information yet, but perhaps they should stay as they are. For example, info_player start remains on the page it's on now, and probably the same for others such as func_door, func_button etc. with no redirect.
I also want to add some example maps that show off some of the basic entities and get some very simple tutorials added. Scampie has written a short introduction tutorial, and in addition there are plenty of old tutorials that can be used as inspiration. Most editor guides also have some good information contained in them.
We will need simple tutorials for things like patrolling enemies etc. and I think these can probably be written up on the entity pages themselves as long as the usage is fairly standard. A short description of setting up path_corners for patrolling enemies could be placed on the path_corner page, for example.
Once all this stuff starts to be added, we will need to improve the organisation of the wiki. One area in particular is to make sure articles are cross-linked better and the index pages need to be much improved and split off into separate games and mods instead of the mess that they are in now.
Here are some reasonably complete example entity pages:
http://quakewiki.org/wiki/Vore
http://quakewiki.org/wiki/func_door
Both are likely to be expanded and improved in the future, but everything on a wiki is pretty much work in progress anyway, so don't worry so much about exact formatting as it's the article content that is most important.