I'm always looking for easy ways to identify inactive players in my friends list, and by far the easiest way to spot them I've found is by waiting a while after an update and deleting anyone who is still out of date.
I generally try to wait a full week but sometimes will kill some after a few days if I don't recognize their names. Today is one full week after the last update, so it's the perfect time to start weeding out the junk players that are causing visiting road blocks and wasting your time when you're trying to find friends to request gifts from.
I've shrunk my friend list down by about 60 players in the last week or two, and I'm already finding it much easier to manage. Because I'm being careful about who I delete, I haven't noticed any real decrease in the amount of gifts I'm receiving... and I'm enjoying the benefit of having a smaller list where I can make sure I gift more evenly among them.
TA DAAAAAA Happy deleting!