I can say the campaign isn't THAT short, it's pretty much the same length you get from other shooters on the market. Name a decent shooter that has a campaign longer than 6-8 hours? Fallout simply doesn't count for a bunch of blatant reasons.
You can choose to rush it, like you can choose not to, and play it casually, these people will finish the game in no time. The main idea is that, with the campaign you get to know the characters, and the game mechanics. It's always like that, it's not a good replayability value.
Echo mode, anarchy are the 2 things that will keep this game standing still. Mostly anarchy.
I can't say for that, I haven't played it, and I can't unless.. I'll let you guys be smart about this and guess it.