Requested feature: Admins should be able to customize post.php by (1) adding or deleting fields; and (2) renaming fields in the UI. For a site with multiple authors, the admin's changes to post.php would apply for all authors.
In MT, I'm able to do this by hacking the edit page. It's difficult, but possible. Naturally, this would present some problems if I wanted to upgrade. But it's possible. In WordPress, because the page is generated by PHP (and because I don't yet know PHP), it looks like it would be very difficult to do this by editing post.php. It's a very large file and I'm not sure if even a good programmer could pull it off. I certainly can't.
Flexibility with regard to customization of post.php would of course always be limited by the WP programmers' need to make assumptions about the type of data the user is likely to put in each field. There is currently a title field, extended entry, etc., and the WordPress programmers have to assume that the title field will hold a title, or something that has a similar role in a published document, or else the programmer wouldn't be able to structure the rest of the software to handle that type of data in appropriate ways.
However, in a community site where the admin is working within the limits of WP's options and plugins to prepare a site that's as appropriate as possible for what the community wants to do, one can imagine many scenarios where the standard form won't suffice, and where changes to the form wouldn't necessarily break the logic of the whole program by stretching data types too much. The WP folks anticipated this to some extent by allowing creation of custom fields on a per-post basis, but that doesn't allow the admin to set up the UI in ways that are most hostpitable to the community. There are a lot of extra clicks involved (and typing) if all the members of the community have to set up the needed fields each time they post. So it would be fantastic if the admin could set up the custom fields and then lock the form so it will apply to all posts.
I'm not a programmer so I don't know how difficult this would be. I imagine it might be somewhat difficult, and at first glance it might not seem like this capability would apply to enough blog sites to make it worthwhile. But I know that there are at least a couple posts on the WP form that ask for this, and some posts on MT forums as well. If you think about it, the design of the write/edit form really controls and limits, more than any other feature of the software, how WP will be used. I suspect a lot of people would think of more uses for the software on community websites if it were possible to excercise greater control over the UI for inputting stories, data, recipes, schedules -- and so on -- into one's database. In other words, since the write/edit form is how you add stuff to the database, the degree of flexibility that you have with regard to what you can do with WP, especially in multi-author community sites, is very much a function of the degree of control you have over the write/edit fields and field names. (Granted, changing the field names in the UI won't have any impact over how the database understands the fields, but that doesn't necessarily have to matter from the user's perspective.)
Adding this capability would certainly give WP a huge edge over other blog/community software. Thoughts?