This is something you will gradually need to adjust to and re-evaluate your expectations of Blu-ray. The problem is inconsistency in the investment in the digitial transfer process by the product manufacturers and the film materials owners who release/license it.
I have about 40 Blu-ray discs, playing them through a Yamaha Z7 AV receiver and a Pioneer LX-91 Blu-ray player. This kit is arguably the best on the market up to the £2k bracket at the moment. So, really I'd expect to get optimum viewing results, however... many of the Blu-ray film transfers leave a lot to be desired and many only offer subtle improvments on the remastered, special anniversary DVDs I own. The background in panaramic shots is the place to see the weaknesses in the transfers, expecially the sky, which is invariably filled with pixelated noise/interference. Another likely factor is the film stock and camera equipment used to shoot the film and what version of prints they have used for the transfer.
The only films that really seem to hit the performance target are films that were released to the cinema more recently (in the last 2 years), things like the Batman films, Pan's Labyrinth, Mongol, Pirates of the Caribbean. The James Bond films are superb, but then they were superlative on DVD too. I watched Zulu today, the print is one of the clearest I have seen, with little evidence of pixelated "noise" in the panaromic shots, which I was very surprised at given its age. The Thing is pretty good, but also suffers from background noise on a lot of the landscape shots. American Werewolf in London is not much an improvement on the Anniversary edition DVD.
Music Blu-rays are similarly inconsistent. The best I have seen is ZZ Top's "Live in Texas," which really sets the benchmark. Led Zeppelin's "The Song Remains the Same," is an atrocious transfer (regardless of the merits of the film... or lack of them).
SonicD