I have never met a PC that hasn't had a weakness. Challenging PCs isn't hard in Pathfinder, killing them is even easier. No cheating required. If you are building your own adventure or encounters, just look at what type of characters they are playing and adjust accordingly.
Nope, a large number of skills is better imo, as it promotes diversity and specialization. I disliked that Spot, Search and Listen were all lumped into one skill i.e. Perception.
I don't have time to prepare my own campaigns anymore, so premade ones are a must for me. I've tried 2 of Paizo's APs and the group has enjoyed them both. Another in my group creates his own campaigns and he runs those, and a third does premades or his own depending on the time he has. I'm...