First, I want to say that I do not hate the game. I dont love it either. I will go over my reasons why I decided to cancel, and there are a few. Keep in mind that the reasons are not in order of why I cancelled.
1) Poor Customer Service: I have never seen worse GMs. Ever. I put in a ticket a few days after early release. I have never gotten anything but a generic response about two weeks later. Really? This is how your GMs are going to work. By giving a generic we are looking into it and never following up. That is terrible.
2)System Requirements: I admit that I dont have a top of the line computer at this point. However, I am still able to play a lot of games with better graphics than TOR without nearly as many FPS issues. PvP is unplayable for me. Ilum is pretty rough as well. Load screens seem to take forever. This also means that my wife will be unable to play at all without significant upgrades.
3)You go from being the CEO of Microsoft to a dude in a cubicle: Basically, you are a complete badass in your storyline. You are saving the Empire. After that? You are just another fucking dude running around the Imperial fleet doing some inconsequential bullshit. MMOs can not have a game over. Finishing my story line feels like game over. The story was great, but I think that it hurt the end game for me.
4) Same quests over and over: There are not nearly enough paths to advance down. You always have to follow the same exact planet order. In middle of leveling some more character, I had a feeling of "whats the point". The class quests are only a small part of the quests. Everything else is the same thing.
5) No LFG or LFD: This was a pretty big one for me. I dont feel like sitting in the Imperial Fleet for hours at a time looking for Flashpoints. Then if you get into one and it falls apart, that is it. There is no signing up for another flashpoint. You have to hope that someone else is running something.
6) Too many fucking load screens: Seriously. WAY too many. As I mentioned before, load screens are fairly slow for me. So, I get a load screen to get onto my ship. A load screen to get off of my ship at an interplanetary space station, and a load screen to get onto the planet. Then the same thing all the way back to the fleet. Seriously. Too many load screens.
7) Everything is the same: All of the classes on both sides are exact mirrors. I know that they do it for balance, but it makes it a bit boring.
8) You get Pigeonholed: You have to pretty much choose light or dark side. Once you do, choosing the other option is detrimental to your chance to get cool items from light or dark side vendors. Not to mention that you want to play one way and your dumb ass companion doesnt like it.
9) Crappy Everything Interface: There are no mods. I am used to mods. I like making gold in WoW. I hate posting shit in TOR because the system is so clunky. It is time consuming, and usually pointless as many people do not even bother buying off of the galactic market.
I am sure that this is not everything, but it is a list that is long enough for me.
Overall, it is a decent game. I may come back at some point when they polish it up and add some of the features they need. Continuing the class story would also be important to me. I dont care if they even add levels. In fact I would prefer they not. TOR was a good RPG experience, but I found it severly lacking as an MMO.