I finally have a few minutes, so I wanted to comment on a few things.
I should say up front that I believe in protecting one's trademark and their intellectual property. This is paramount to anybody who works in a creative endeavor.
That being said, this is a classic example of "what not to do." Here are a few thoughts I have on the subject:
1. The trademark is a weak one, as several others have mentioned above. It doesn't stand out like Dragonlance, Dungeons & Dragons, Deadlands, etc. does. I could easily see any number of fans coming up with the name without ever hearing of Lone Wolf.
2. Lone Wolf is not a well-known brand. They can't afford to be making enemies. If they were the NFL, then maybe they could. Right now, every dollar counts, and putting off fans is not the way to go.
3. Are these fans costing Lone Wolf any money? If it was something like Ema's Character Sheets, then I could see that. But from all accounts, this is just the work of fans with no money involved and doesn't have anything to do with Lone Wolf's particular Army Builder.
4. You do not build a house when you're busy tearing someone else's down. When you go after fans and Privateer Press like that, you're not building a fan base.
5. What is your legacy? When we think of TSR's web policies, we remember how they were tyrants, shutting sites down. The company is long-gone now, but their internet legacy remains. Lone Wolf has just created a new legacy for themselves, one that portrays them in a negative light. People are going to remember this, and this will do nothing but hurt the brand.
6. Pick your battles. Decide for yourself if this was worth fighting. Don't fight a battle just because you can. Look at how WotC handles things. Now, I don't always agree with them, but generally they leave fan sites and fan works alone. They only send out C&D letters to those who infringe on their ability to make a profit.
7. Build your fan base. If the use of Army Builder on another company's forum is endangering you, that's a problem. Instead, focus on the positive, and build up your Army Builder brand, preferably on your own forums and in more public places like EN World.
Personally, I feel that this move will hurt Lone Wolf for some time to come. They have just put off several potential customers, and perhaps angered some existing customers. I know that I won't be buying from them any time soon.