Added all clips that are either useless currently or don't fit into a run to the spreadsheet just to keep track of them. Not going to bother naming all of them since that only makes sense if they're used. After testing it some more, Dwarrowdelf Skip may be moved to that list if it doesn't work well in an actual run, I've only done 1 run through using it so far, so I can't say for sure yet.
I found a different spot in chapter 4, it requires 1 less fight than the one you found I believe.
Found a few spots to clip out of in Chapter 4 and 5, but none of them seem useful unfortunately. In Chapter 4, if you manage to get behind the Uruk-hai bonfire, it just plays the same cutscene as if you approach it without gathering the elves first, just with no audio, then it forces you back in bounds because it places you at a specific location after the cutscene. In Chapter 5 you can clip out of bounds to skip Morwen, but that stops 2 of the rider groups from spawning and I cannot find a way to get around the bridge without them. Also in Chapter 5 you can clip out on top of the first hill to your right when you enter the town of Rohan, but you're surrounded by in bounds areas and can't get anywhere useful. Wasn't able to find anything in my run through on chapters 6 or 8.
As mentioned previously in this thread, we probably need a better way to keep track of these. Made a quick spreadsheet with links to each clip's video. Clip names are tentative, if anyone has better names let me know. https://docs.google.com/spreadsheets/d/1Se9KY0POEj-1P0ATywYQNfo05vK_3SIQqKl02mg6tWQ/
After testing, that last skip I posted may not be worth it. If you don't do those fights you won't have perfect mode for the last fight of Chapter 2 which makes it almost impossible without crazy luck since you're under leveled if you've done all the previous skips. Still good to know its there though.
I doubt anything more with Chapter 1 can be skipped, unless you're willing to skip Elegost and/or Hadhod. I found 3 spots that can easily be clipped through in chapter 2, but none of them seem useful because so often you're going up and theres no way to gain height without some sort of terrain with collision, and its mostly just darkness from what I've seen. I can record where they are later just in case someone finds a use for them though.
Welp, thats what I get for not testing things before doing a run. About 10 minutes after I posted that, I found a faster clip to get to Hadhod after Elegost. I don't think the Troll and Watcher are possible without Elegost, so this one seems better. New clip is at 8:47 youtube time, 8:40 Livesplit time.
Just did a test run of Chapter 1 using these clips. Haven't polished/remembered the movement so it is very sloppy. Saved quite a bit of time but it makes the required fights much harder due to lack of levels, and I fear for full game runs you wouldn't get all the Skill Points needed for certain abilities that would make that easier to deal with.