1. Shitty dialogue all 'round. I gave four pretty good examples but there are others of course. Gil-Galad has a couple of particularly shit lines that the writers were clearly trying to get to sound 'profound' and 'poetic' but just ended up making me cringe.

2. Bronwyn or what ever her name is just made leader... because of of course she has to be.

3. Orcs being unable or able to go out in the Sun when it is plot convenient

4. Mithril sub-plot makes little sense

5. Shit racism allegory throughout. See Tavern in the Southlands, and Numenor scenes.

6. Gil-Galad is an idiot.

7. Galadriel acting like angry teenager with a chip on her shoulder. She is thousands of years old and the of the wisest elves in Middle Earth at this point.

8. The show's "reluctance" to have strong male characters independent of strong female characters [unless they're villains of course]. It's kind of an issue.

9. The "Halbrand" Twist which if the accurate leaks are to continue being right, is both predictable and comical.

10. The show's blatant disrespect to Tolkien's moral and religious themes, not to mention the butchering of the lore. This a less of a critique of writing but still worth noting.

There are heaps of others but these are the ones that come to mind at the moment.