is quite possibly the best example of a series that suffered due to network interference. Alias
was a show ahead of its time. It was smart, complex, heavily-serialized... but when it aired, networks hadn't embraced these qualities yet. ABC wanted a ratings hit, so they kept asking the producers to make it "more accessible" to viewers (aka "dumb it down"). There were creative decisions that were made because the network demanded it, and it had a negative impact on the series. A lot of story threads do not get the attention they should.
The first two seasons are absolutely amazing. Things definitely change in season 3, though I still found it entertaining and good enough. Season 4 gets off on the wrong foot, and spends a good chunk of time going nowhere, before finally coming together in to a sloppy and rushed climax. Season 5 was more consistent storywise, IMO, and has some great moments, but there are just too many cast changes for my liking.
If you're interested in Alias
, I highly recommend checking it out. Even with the decline in quality, I always found the show to be entertaining.