I think that ToES is environmentally the weakest of the three instances. It's still fine for the most part. I don't think that Lei Shi is that bad either, but the design might've fit an earlier position in the tier better.
It was extremely long, yes. I remember it clocking past 20 minutes in the beginning even with the nerf to the first phase. It was an interesting design that I think could've ultimately been improved a lot. I kind of liked the idea behind Lei's Hope, making the fight feel like two encounters in one.
My biggest issue with the fight was how bland the phase two environment was. I was originally expecting something dark and swampy.
I thought it was one of the tier's finest.