With assignments, grading is easy- you give feedback in the window, and have several buttons, with the option of saving and moving on to the next item, or closing the window.

In forums, not so. A typical forum with feedback takes several steps to complete with grade and feedback:
- click on submission (assuming each person posts one forum, the only way with a very large class)
- read, and assign grade and submit
- wait for page to refresh (3-5 seconds) or advance by clicking link and letting page reload
- clicking reply, waiting for that page to refresh
- typing in reply and submitting
- wait for page to refresh (3-5 seconds) or advance by clicking link and letting page reload
- click on navigation/breadcrumb trail to go back to list of posts

This is OK for a few posts, but when you have classes that rely heavily on forums (public, sharing, constructivism, all that) you end up a LOT of this type of grading and it gets to be a real pain.

Suggstion for resolution:
- have a 2nd button on the post that says "submit grade and reply" or have that as an option in the forum. So when you click it after putting in a grade, it submits the grade and then jumps forward to the reply page, shortcutting several steps.
- have a 2nd button on the reply page that says "submit and return to forum" which will take you back to the list of posts, not the thread you just finished with.

This would reduce this whole process described above to:
In forums, not so. A typical forum with feedback takes several steps to complete with grade and feedback:
1- click on submission (assuming each person posts one forum, the only way with a very large class)
2- read, and assign grade and submit and reply (added button)
3- typing in reply and submitting submit and return to forum (added button)

Downsides? Well, it provides more buttons, but this is one place that has hardly any, and in this case oversimplistic means too much work, esp. with a slow connection. Its possible the newbie would be confused by the 2nd button on the reply page- wondering what the difference would be- a few times they'd learn one returned to that thread, and another to the forum with all threads.