Real Rating: 2.75
Think I'll follow on what a lot of people said.
Haruhi is most definitely a trend-setter series in lots of ways, it came at the exact moment of the rise of anime forums and chatrooms, it revitalized the Light Novel industry, had surprisingly meta and self-aware themes - albeit way too on the nose and rather badly executed - and it renewed a lot of classic dere types, breaking away from the "violent-love" tropes.
With all that taken into account, Nagaru Tanigawa doesn't seem to try any kind of subtly, at times it felt almost insulting, explaining everything plainly, it's like the book is constantly trying to make a point about being around Sci-Fi, which it's simply not. Lots of boring pseudo-commentary, it's too bad, because the anime adaptation did sincerely try to be bold, with the infamous 8 looping episodes "Endless Eight", yet even then, it all felt tacky - the series is too focused on making itself sound smart rather than using its medium's tools to argue that, and it somewhat feels insecure about it too.
Either way, I deeply respect Haruhi for its cultural impact, both on internet culture and on the industry, and I certainly salute the continuous efforts of the author to offer something interesting every new volume, but re-reading Haruhi truly felt like a chore rather than something i'd want to do on a Sunday afternoon.