Short Answer: No, they are not...
I've been in the market for checking out free games on the internet for a long time, having to do many searches and trying out different games to figure out what I like. It was pretty depressing finding out that I hate most of them. I started calling MMORPGs "clicky-clicky MMOs" because 90% of the game is me just clicking monsters and watching my character beat the crap out of them while I alt+tab and do something else. I wasn't the least bit interested in the stories because they usually start the same way with a different setting. "Hello, RandomAdventureAmongMillions! We are in turmoil! It is up to YOU, specifically, to kill those demons/dragons/puppies!" Hence, you go out and kill enough monsters to render them all extinct. And so do all of the other million adventurers there. Oh no! A particularly large palette-swap of a monster is approaching! Throw adventurers at it until it dies!
Most of these games have a very big, very noticeable problem. That being that they suck. I understand that attaining the best graphics and models isn't always possible for Free games, since you need to appeal to as many people as you can, and not everyone has a good computer. However, gameplay is different. Whatever I'm going to be doing for 90% of the game, I want that thing to be fun. Is it killing monsters? Make it flashier and cooler. Is it sitting around looking at NPC words? Add some animation and humor. Is it talking to other players? Uninstall-*COUGH*, I mean add more customization features. I look at most of these games, and one thing is clear. They are rarely fun, and many of them are the bare-bones of a normal RPG experience.
Go play a console RPG. You will notice some significant differences. For a good example, let's use one of the most well-known ones: Final Fantasy. You go out with a party, kill insane amounts of monsters for experience points, increase your character level with those points, and then kill stronger monsters. You also experience a gripping tale of fantastic magic and memorable, unique characters. Once you finish, you feel like you actually saved an entire fantasy world from utter destruction. Or something. Either way, MMORPGs are just that first sentence. The entire point of the game is leveling up and literally nothing else. You will not remember the storyline, you will not remember the characters. You may not even remember who the crap you were playing as. There's a reason for this. And this is because you are playing a horrible game.
Are MMORPGs worth playing? No, they are not. They never are, and there's a good chance they never will be.