I'd like to expand on what
@innerdude (and a few others) have touched upon in their posts.
@Retreater I can appreciate that your experiences are your own, and that your opinions are valid. However, it seems to me that you're trying to find "D&D" in games that are not specifically D&D (looking for D&D in all the wrong places?). That hardly seems fair to some of these systems that are not trying to be D&D in any way, shape, or form. It is no wonder why most of these games failed to meet your (or your groups') expectations.
I'm not saying you shouldn't if that is exactly what you're looking for. But you should agree that some of these systems will never satisfy anyone's tastes unless they can change their expectations. Just because two games are labeled as "RPG", doesn't make them the same. Likewise, just because D&D is labeled as an "RPG", doesn't mean it is the best one to handle every style of play. Understanding what it is about D&D that makes it "D&D" helps to decide what you're looking for. More to the point, recognizing it's strengths and weaknesses is as important as deciding what you like (and not like) most about it, and RPGs in general.
I'm going to touch on one example that you gave because 1)I have had a lot of experience and success with it, as well as dealing with people who haven't, and 2): it is one of my favorite RPGs to date:
Star Wars (FFG)
Extent of Experience: Ran a short campaign
Status: I never really understood the rules and how to translate the dice pool results. I had to have a co-GM basically handle the rules issues for me. Easy for characters to get so powerful that they were unstoppable except to be challenged by “story moments” (“this whole Star Destroyer is going to blow up in two rounds and there’s nothing you can do about it.”)
Verdict: Won’t run again
Star Wars by FFG (Edge of the Empire)
Extent of Experience: Ran a 6-month-long campaign; several beginner games at LFGS and Con; some PbP attempts were made, but ultimately decided the system was not well-suited for that format.
Status: Still my favorite RPG system. I am looking forward to introducing it to more people in my new home state (WA).
Verdict: This was one of the first true non-D&D RPGs I looked into when I decided I was done with D&D for a while. Like many others, my first attempt was to invite my (at the time) current D&D group to give it a try. Without having any experience or realistic expectations of how the game was played, we collectively made the same mistake of bringing along our normal expectations of a D&D game.
After a couple sessions, I could feel something was off. My players were feeling it, too. Combat wasn't interesting. There was no "loot" to hand out. It was difficult to gauge how powerful any of the PCs or the NPCs were, thus making it difficult to balance an encounter. That's when I realized our mistake: we were all trying to play D&D with a completely different game!
Since then, I now tell everyone who shows any interest that this game is
not for everyone, and it is
nothing like D&D. D&D is a game based primarily around combat, power levels, and collecting treasure as power ups. This game is about collaborative story-telling and improvisation. Not every battle needs to be won. Not every obstacle is a fight to the end. Characters do not need to be exceptional in combat in order to be useful or effective. The same dice results can vary, as every instance in the game should be unique.
These are lessons I had to learn over time. But I would've never learned them if I hadn't learned my first lesson, which was to stop thinking that all others games played (or should be played) like D&D, or anything else. That is a rule I now apply to every new game I try, even the ones like D&D.