What kind of guild are you?
First off, before you do anything else, it's important to go back and look at what type of guild you advertised yourself to be. If you billed yourself as a casual guild with little to no pressure and you're unhappy with someone who is casual and not exactly a top raider, then you might need to make adjustments to your guild vision and be clearer about your expectations from future members. If you're a hardcore guild, then you need to look at why he's there in the first place and whether your screening process did its job or not.
Friends and family -- not so family friendly
Of course, there are always exceptions to the rule when it comes to new members, and one bugaboo is the old "friends and family" policy. It's hard to tell a longtime member that her husband or close relative can't join, but all too often, you end up with a Mr Wiggly on your roster if you agree to invite.
You can mitigate the potential for drama, however, by communicating beforehand with the member who wants to get a tag for family or friends. Often, the member knows whether or not the invitee is any good, and the member can become your ally in managing the family member's expectations once you've done the invite. It's a tricky triangle, with the leader, member, and family/friend as the three points; there's potential for two of those three to clash with the third. If you can get everyone involved on the same page from the start and you make sure to keep the lines of communication open, you can avoid problems later on when you have to make tough decisions.
Is he taking a spot that someone else deserves?
If you've been proactive in setting clear expectations, then it's easier to deal with tricky issues like deciding whom to bench on raids. It doesn't matter if Mr. Wiggly is married to your raid leader or your heavily geared-up main tank -- if someone else is a better player and more deserving but is sitting out, he needs to be in the raid.
Make no mistake about it: This brings a huge potential for drama, and there is always the chance that you might lose your top raider as a result. But then again, raiding is all about teamwork, and if that top raider can't see the bigger picture, chances are you'd have a clash over something else down the road anyway.
Can you hide him?
Suppose that there is plenty of room on the raid. So much room, in fact, that you've invited alts, bots, and bots of bots, and you've even tried to stick mage pets into raid slots, but you still have space. And let's face it, Mr. Wiggly is a likeable guy and always tries his best, so try to figure out if you can take him on the raid and hide him. With some scripts, it's impossible to do that, either because the boss selects him to do the appropriate reaction or because he'll get hit with some sort of effect that he has to deal with. In those fights, you'll probably have to have him duck out or just die and stay dead for the duration of the fight. But in many raid fights, there are easy tasks you can assign to Mr. Wiggly that will allow him to contribute and not pose a danger to himself and others. If there's a lot of movement involved, pair him up with a patient, sharp, reliable guildmate and tell him to never leave his side.
That can also go for raid calls in chat. Honestly, it can get pretty chaotic during a fight when the raid leader is calling out instructions to specific individuals on the raid or groups (like healers or tanks) in addition to general instructions to the entire raid. If Mr. Wiggly has a hard time with information overload (and honestly, I've had some Mr. Wiggly moments when it comes to this), have his "buddy" macro a few brightly colored messages that help enforce key raid commands. It's a simple step, but it can make the difference between success and yet another "Wiggly Wipe."
Listen to members, but use your own judgment
This is probably the hardest part of all because if you have a Mr. Wiggly in the guild, some of your members might not have as much patience with him as others. Frankly, they're justified in feeling that way. You need to make sure to listen to their concerns, but convey the bigger picture if there is one. Yes, Mr. Wiggly makes mistakes, but does he make up for it in other ways that have helped the guild's progression? If so, that member needs to hear it, and hopefully you both can come to an agreement.
The bottom line is that you need to use your own best judgment, and if you've built up a foundation of trust within the guild, chances are that members will be understanding in whatever you decide to do. But if you do keep him in your raids, make sure he doesn't fight with a spoon.
Do you have a guild problem that you just can't seem to resolve? Have a guild issue that you'd like to discuss? Every week, Karen Bryan takes on reader questions about guild management right here in The Guild Counsel column. She'll offer advice, give practical tips, and even provide a shoulder to lean on for those who are taking up the challenging task of running a guild.