Killzone 3 trophies look really easy compared to K2. I was planning on getting Killzone 3 day 1 and jumping straight into the multiplayer to get that pesky top 1% trophy right away should it return. With Killzone 2 I played online for 2 hours during the first week of getting it and I didn't even try to, but I got in the top 5%. Then many months later I had to clock in over 40 hours in one week to get in the top 1%.
I'm glad the top 1% isn't required this time (assuming the 20 hidden trophies are all story related). Either way I'm not going to make the mistake of waiting too long to attempt it again.