Things I Want to Do in Gmail and Can’t

On the whole, I like gmail. I've almost entirely switched over to it, and the more I use it, the more I find that I like it. (That's as opposed to some of my friends, who can't stand it.) But there are several things that Google still needs to fix:

1. I can't change the subject line of a reply, even when the new topic is obviously unrelated to the original subject matter of the thread.
   
2. I can't insert pictures into emails. (I can attach them, but that's not the same thing by a long shot. Would Picasa or Flickr be as popular as they are if you had to download the pictures manually to see them?)
   
3. I can't get a horizontal line to show up between replies, a la Outlook. This is probably just stylistic preference, but I like an <hr/> element to show up between replies in a thread, to make it easier to see where one reply leaves off and another starts.
   
4. I can't easily delete a single email in a thread. The vast majority of replies to a thread don't need to be saved, and just clutter things up if you don't get rid of them. But it's a pain to select each individual response (the thread is initially collapsed, of course, so you can't easily distinguish between responses), and then with my mouse choose "Reply/Other Actions", "Delete", "Yes". There should be a single keyboard shortcut for deleting the current message, just as there is for deleting the current thread.
   
5. I can't easily select multiple items to perform an action. There are times when I want to select, say, 20 contiguous emails in a list. This is easy in Outlook: select the first, press shift, and then select the last. But in gmail you have to select all 20 individually, either with a mouse (uggh), or (slightly better) with the keyboard.

Don't get me wrong: I'm very grateful that Google has at last added offline capabilities (which was a pretty neat trick for a webmail package), and the search is dramatically better than Outlook (or at least much faster). And a whole new world opened up to me when I figured out that gmail had keyboard shortcuts. (I should note, however, that gmail's keyboard shortcuts are of the utterly unintuitive, only-an-engineer-could-have-thought-of-this variety: how else do you explain "#" == "delete", "e" == "archive", and "u" == "return to inbox"?). But now that they've got the big stuff nailed, they really need to finish their UI.