In this question, I found a similar question of mine (just that mine is about a problem of the new system) so I answered with the "new" method.
- I know how to edit the play list (at least I can remove videos) while being playing (I won't do a screencast just to demonstrate it, an image is enough)
- Youtube system has some limitations, that I try to workaround.
- Is the most similar to the old system (where I could edit things around), was a new addition that thanks $DEITY they deployed which is also what OP wants.
Lets see why answers can be deleted:
- commentary on the question or other answers? not a comment, it solves OP's question
- asking another, different question? I don't even use interrogation sign
- “thanks!” or “me too!” responses? I have upvote privileges, why I should put "thanks"
- exact duplicates of other answers? not found in any other site
- barely more than a link to an external site? not even links, but screenshots
not even a partial answer to the actual question? HA! Lets analyze deeply OP's question:
how do I delete and rearrange videos in a playlist like in the old YouTube?
My question answer the "delete" part, and makes the note that is still not possible to rearrange (or at least drag and drop doesn't work).
So, what I got here? A downvote out of nowhere, and a mod deleting my answer without reason. Is this how the community receive potential new answerers? Have anyone took 5 minutes of their time and check if my answer is correct or wrong at least? The actions that were taken makes me strongly believe that it was not. Nobody stopped to comment "hey I saw your screenshot but I don't see it, why is that?" I would gladly say that is available to HTML5 and Flash supported browsers, I'm using Firefox and Chrome and in both I've able to use it. Something was not clear? Comment! I do my utmost for being as understandable as possible, verbose until the insanity just for the sake of VERY GOOD ANSWERS. So, can someone do a very good answer explaining why my answer was deleted?
To give participation to >10K rep users, here is a screenshot, since they can't see other users deleted answers: