Some points are valid but not all. I like the quests, I've been bored to hell with so many games lately where are not enough quests. I wanted to get the game finally which would be like good ol' Baldur's Gate series and this is closest. Not exactly it but still close then anything else.
There are bugs but not with the quests you mention. I was able to complete them all, you really need to read quest text and also the appropriate codex entry if the quest has such. Only slight issue I had with the quests is that at times when you complete the quest and journal says that it's done, the NPC still may have the quest icon above his head, like Slim Goudry in Denerim. Or sometimes you finish the quest chain and you had more then one path in it, you chose one and finished it but second option may still remain in the journal (like king quest in Orzammar, if you're diplomatic enough you can "play along" with both sides all the way until the end, but when you finish one branch of the quest, second one stays in journal). Or when you advance some quest not in order, that is, skip one NPC and speak with next one (like Wynne's quest, you may skip the fella in dalish camp and complete the quest and he will have this quest icon hovering above his head regardless). But other then that, so far I've finished every single quest I've got so not too bad.
Bugs, yes, there are those. Some gameplay issues too, like equipment related - I agree that there should me MORE MODELS for armors and weapons. All massive armors look the same, with just different texture. Yeah, it's kind of lame but not game breaking. Same with weapons, there's the certain selection and then that's it, only difference is in materials. And of course the fact that some items don't even appear in the game, either because of the bug or because of the randomness. Like Chevalier's armor - I've never got the whole darn set! I can buy one piece and other pieces may or may not appear here or there and at times they don't appear many times in a row. There are few "sets" which I've never had as a set because of either this randomness or bugs. Blast it, if it's a set, put it in game and don't mess with it, as I see it. But other then that, it works so it's OK.
Alignment, I like it. I never really liked the system in many other games where it's immediately and obviously clear whether one's "good" or "evil". It's never clear. It's supposed to be blurry and it is determined by your choices and your actions. I am a "good" guy but I am no "do gooder". My chars do what they feel is right and this doesn't always match the world's view on what's right and my char doesn't care about it. Most of his actions may be considered good, but there are also actions what would make others raise their eyebrows, scream out from horror or run for the hills.
In the end, the point is that this game has it's share of issues, sure, but none so far have been gamebreaking for me and I've had fun. Heck I've played it through several times and in many cases I even restarted in mid-campaign because I wanted to try something different suddenly. That's why I always save one game at the start of each area and keep it, so that I could replay the whole area if I wished so. As more custom content gets added (sure it may take time as the toolset for this game is not exactly user friendly and easy to use but there are smart people out there who'll figure it out) it'll get only better. So the way I see it, it's quite OK and it can only get better so I definitely won't return my copy. But, good luck to you OP, your choice is your choice.