1) Not having a difficulty setting IF the game is difficult. If your game is too hard, I WILL stop playing, and there will be so much wasted effort
2) Making bland characters. Please make likeable characters. They are what help get me invested in the story
3) Having really cheap plot twists. Don't build up some big thing, get me all intense in to it, and then use some cheap cop out for what it really is
4) Not having any sidequests. Sidequests are great for when I want to play the game but I'm not ready to continue the story or just need a break from it
5) Having way overly sexualized characters for EVERY character. I can forgive it some, but if my whole party is giant breasted women in bikinis who are awkwardly blushing and standing in suggestive poses all the time I will throw that game out
6) Not having any magic. I want magic in my RPG's. I don't care if its only certain characters who can use it, if its everyone, if you buy it, if you learn it as you level up, whatever, just have magic
7) Make it fun. There have sadly been a few RPG's I've had to read the transcript for because the story was great, but the game felt like a pain to play. Either the battle system was too complicated, or it was just boring. Make it a joy to play