All the talk seems to be like those "attack fads" or "praise fads" that appear from time to time. There was a praise fad for Heartcatch PreCure cleverly started on 4chan and it sprung up like wildfire and spread. There was that attack fad in the early days of GitS but that was overturned fairly quickly. But it was amusing to see people parroting it out of feeling smart for following that fad.
A lot of people on 4chan who post about how predictable the plot is are misusing the word. What they actually mean is that they have seen parts of GC in other shows. For example, the beautiful girl is hurt, there is a robot, bombs explode, blood appears, etcetera.
Now, let's have a unique anime show. Remove all blood, all fire, all water, all people, all cars, all robots, all ground, all air, all metal, all electricity, all guns, etcetera because they are all predictable and things we've seen over and over and over and over again.
Anyways, familiarity of similar items does NOT equal predictable even though a ton of 4channers misuse the term that way. If you look at Guilty Crown for discrete events, then you might analyze the show in terms of being a sequence of events A, B, C....Z...AA, BB...ZZ, etcetera. Discrete event A was reminiscent from CCS, B was from macross frontier, C was from Bubblegum Crisis, D reminded you of Code Geass, etc. I find many parts of Guilty Crown familiar, but not predictable. If you had challenged those people who said the plot was predictable, then after watching episode 1, they should have been able to outline episode 2 without watching it. I bet they can't. Their complaints about predictability only occurs AFTER they have seen it and that makes it hypocrisy. It seems more of that "I look cool and get attention for dissing a hot looking show" especially since the people who say it sucks keep on watching it.
All these people claim that the show sucks so much that it forces them to AVIDLY and EAGERLY wait for it to appear and they boldly CHEER HURRAH when the subs appear and they skip work just to download it and accept no interruptions in their life in order to INTENSELY watch the show with GREAT ENTHUSIASM before they then pronounce to the world "This episode sucks and was soooo predictable!"