I think the assumption is that essentially all older players will have cleared out their friends list at some point. And if they haven't, then they must have a bunch of inactive friends on it, which doesn't seem like an advantage to me.
That is exactly where I am right now. Until the tavern came along, I just went down the list and hit the Aid button on everyone. I was still getting my 20 coin and my chance at a BP. It didn't affect me if they were inactive. In other words, if I had 50 friends, and only 40 were active, removing the 10 that were inactive did not change the number of people who might have aided me in return, but it reduced my chances at a BP and my 20 coin. I also like to give others the benefit of the doubt about inactivity, since this is, after all, just a game. Real life does impose its priorities, and sometimes someone is just away for a while. I hate to cut someone off from my friends list just because their priorities are focused on real people in their lives.
Now with the tavern, it is more obvious to me that some players are inactive long term. I can't visit the taverns because they are not clearing out the taverns. That is even more annoying outside of Beta, and I'm looking forward to the changes they have put in there to identify whose taverns I can visit right now. But another thing that is different is that the tavern is getting people more eager to expand their friends list. I get at least one friend request daily in each of my worlds now, and my list is growing steadily. It is nearly full in some worlds, and removing the inactive players from my list now makes a difference. Until I do remove them, I will not be able to receive any more friend requests soon. So it is only now that I'm wanting to clear out those absent friends.
One of the goodwill things I have always done is aid someone as soon as I accept a friend request. I can still aid right away, but as soon as I hit my 20 deletes, I won't be able to help them with a tavern visit at the same time.
That's just the perspective from where I sit. Eventually I will need to clean out some obviously inactive players, and I will hit and pass the 20 removals mark. And life will go on. But it is not the way I would have set it up had I been asked. I think a "you can remove this many a ___ [fill in time period]" limit would have been the way to go to account for situations like mine.
Thanks.