Sure, I'll give my hot takes on these:
1. Long Monologues/narrative descriptions/cut scenes;
This honestly depends. I've had mixed results with doing this myself, and find they work best when providing exposition for the players without their characters present. I know some folx on here will cry heresy about meta-gaming but I've found players appreciate having background information and that it also doesn't impact the way they play their characters (other than the players themselves being more engaged). You can definitely go overboard with it, and it never works when PCs are actually present.
2. Focus too much on NPC talks;
Yeah this can be a huge pain, because it's also basically inevitable anytime the PCs are in a room with multiple NPCs. As long as the entire conversation remains interactive (ie not a "cutscene") you can get through it well enough though.
3. Wait for the "perfect" moment to introduce a new/replacement PC;
I can get on board with this, honestly, though the likelihood that I am to see a PC death in the middle of session is rare enough on its own (my sessions are relatively short as it is). If the beginning of a new sessions isn't the "perfect" moment though I don't particularly care. I don't want somebody sitting on the sideline for however long. Especially since I also occasionally have spotty attendance from week to week.
4. Plan for Three hour long fights;
Unless it's a season finale, definitely not. That said, I've found the Dimension 20 model of "big combat set pieces" vs multiple smaller encounters works so much better at the home game level. It eschews big dungeon crawls and the resource management game but frankly I see that as a feature and not a bug. And before you say "if you don't care about resource management game you shouldn't be playing-" look I know I KNOW. My hope is D&D is the gateway drug. Like with actual drugs, however, I've learned it doesn't really work that way.
5. Putting the story before the game;
This is a personal preference thing, but the story is the point of the game. We roll to add tension and uncertainty, but the collaborative storytelling is the end. The dice, the stats, the game? That's simply the means.
6. Have temporary characters that are planned to be killed off;
Naw, this can be really effective, especially if your player is the one that comes to you with the idea. The most reason season of Dimension 20 also sort of does this and it's great.
7. Allowing PVP or truly high tension Player moments;
Again, personal preference. I don't personally allow PVP actions; my PCs do not roll dice against either. Intraparty conflict plays out through role playing, period.
8. Letting characters talk endlessly;
I have yet to meet a DM who hasn't told at least one story about how they didn't have to say anything for like a half-hour/hour and it was one of the best moments they've ever had. It's a beautiful thing. That said, I guess it can also be a personal preference thing, I guess. But I can't imagine the DM who after twenty minutes of the players chatting/arguing/plotting in character is super antsy to put the kibosh on it and get the show on the road.
9. Setting expectations too high.
Sure, I guess?
