Yeah I found Re:Zero, Akame Ga Kill, and Sword Art Online to be disappointing.
The reason why these animes are so interesting at face-value is because they have great premises. But their plots are ass in my opinion.
Akame ga kill has flat characters with almost little to no meaningful character development. SAO has a nonsensical plot. And Re: Zero isn't outright bad but doesn't do anything special that I haven't seen in other animes.