I don't think any form of entertainment has improved more over the last 30 years than TV drama series, so I can see where someone looking at it for the first time today might not think Twin Peaks was anything special. But at the time, there had never been anything like it on TV before.
I loved the series back then, and find it holds up pretty well today. As mentioned, there are some low points in Season 2 ( a certain plot involving the Civil War is particularly terrible), but the high points ( the episodes leading to the reveal of the killer, as well as the finale) more than make up for it.
Unfortunately, Lynch was held back by the constraints of network TV in the early 90s. The Return season on Showtime was his peak. I've never enjoyed a season of a TV series more than that one.