Yeah, The lack of a solid villain is one of my personal biggest complaints. There are occasional small villains, but they usually amount to nothing by the end of the episode. If you scroll up a bit you'll see the rage I went into when they "redeemed" arguably one of the most evil characters on the show. Out of all the characters they introduce to fill the role of "villain," most end up turning good, or their arc is completed within the same episode and they aren't seen/heard from again. I don't know if you've watched Avatar: The Last Airbender, but it would be like Zuko turning good in the third episode, rather than the third season. Keeping in mind that MLP has almost no combat and is mostly slice of life episodes, as you have said.
In spite of that, I still watch it mostly for the humor and the characters. You've watched a few episodes and didn't find it to your liking, so you are freed from watching any more. To each his own!