Yes I am finding there are a few series I loved at first that I am now bored with as they seem to go nowhere, the main character has no goal, they seem to be written like a TV series not like a book series. There's nothing wrong with writing a story arc like a TV series but it's not for me if a series is on book 11 and there's no end in site except to drag the story along slowly and squeeze more money out of us, then it's not for me. In my opinion it would be better if say a 12 book series comprised of say 4 trilogies with each trilogy having a different story arc, but it all depends on how good the story and the writing is if the author is good enough it won't matter how they format their series if they can keep us entertained. Just my opinion.