If you really think about the term free, is anything really free? I am in a similar boat like you. I have never found an mmo that can keep in interested for a long time. Paid, buy, or free, they all had some sort of flaw that led me to quit them. I liked ffxiv, still do and sort of miss it, but I thought the end game is way too boring. In the end ffxiv is all about gear progression once you reached cap. The way you do that is to grind dungeon over and over again until you have bis. I also hate ffxiv story as well. Not that they probably have a bad script. I just hate their English voice acting and the subtitles for other language is based on English voice. So if you do switch voice over to other language you're getting completely different meanings.
There are some games that's said to be great, gw2, but in my opinion you're not gonna like what you find in there because ultimately you're going to be tunnel to more specific content.
I've heard swtor is great for story, as the same for tsw. The only bad thing about tsw now is that they made lots of bad changes to gameplay (imo), and are focusing on wrong aspect of the game. For example, they are now working on a tv series instead of polishing the game. They only made one core change and that is to work and force with the reticle system.
There isn't that many great "free" mmorpg games out there. The ones that is paid or buy are usually of higher quality but in terms of story or focus of content they are lacking.
