I just hope they make it really hard. I know I can't speak for everyone, but I find that difficulty increases the value of my games.

Actually I find it can put me off. I don't have a lot of time to replay the same bits over and over and over again trying to get more 'skillful'. I like to be able to finish a game without having to devote hours of my life I just don't have to spare. Got so many unfinished games on my shelf that have just lost their appeal. Whereas the first Uncharted felt about right to me and I finished it, and I've played it a lot since. For me how fun a game is after you've finished it is important as you'll play it again and again and that's what increases it's longevity.