I can certainly understand your position. Our guild is/was in it just the same.

The problem with keeping around the players that you already know that you want to kick is really mucky though. To start with, your other raiders are going to notice the mistakes or issues that this player has. They are going to know that this person doesn't belong in your guild, and they are either going to talk about them (which can easily spark a load of drama that you don't want) or they'll start thinking that they can act the same way because their spot is just as safe.

Not only that, but it get's tricky for the member you want to remove as well. How long will it be before you have your numbers up again? I doubt anyone knows the answer, so all the while that you are looking for recruits, you end up stringing this guy along without him knowing that he is going to be removed the moment that you get your numbers up. That's just bad form, and it is really insulting to the player as well.

All guild struggle with similar issues during the summer - all of them. I know many world top guilds that still have attendance issues every single summer because people take vacations and breaks and other things. It happens. The best you can do is just doing the best you can do; part of that is not sacrificing the principles of your guild just to snag a warm body.