Invites
The invitation limit of 80 is fine, even the total of 140 is fine. What is not fine, is that if you want to add a new invite but have 95 on your list, you have to remove 16 of them to be able to invite the one even though 30 of your friends might have made the approach to you.
The only way around this, though, is for the system to track which friend you invited and which friend invited you - data I don't suppose is currently being stored. If that data is stored (even if not available historically) then it would be possible in the above scenario to invite another friend, because you will have only invited 64 of your 80-invite limit.
As an optional enhancement, the rules could be changed such that, of 140 possible friends, 75 may be invited, 55 may invite you, and 10 can be either. This does a number of things:
- It would leave the possibility that you still have the difficulty in having to clear out some friends just to be abke to invite one more.
- A new element of strategy is introduced, as people try to make sure they have 65 invites, not just 55, keeping their list flexible.
- If, as I presume, there is no current data on whom invited who (or should that be 'who invited whom'?) then all historical friends can be put into the 'either' category and rules applied forward, limiting the 'either' to a maximum of 10.
Pinning
Pinning has limitations: you pin six but then want another friend in 2nd position, your only option would be to unpin five, pin the new one, then hunt for and repin the five you unpinned.
Rather than pinning, I would opt for drag-and-drop to put friends in the order you want. The position would have to be initially placed in order of appointment (less useful than the current ranking) but could then be moved into any order you like. Even easier would be a full-screen showing many lines of friends, making moving them about much simpler.