TL2 is going to use Steam Workshop, isn't it?
That is already a pretty full-featured mod manager, including auto-updating and some other nice features.
Wow, years later and I'm resurrecting this thread. Here goes the main Copy-Paste!
I'm Webbstre, the Administrator and former owner of Runic Games Fansite. I'm going around trying to find places where people have linked to or mentioned our previous mod manager tools and update the conversations with info about our latest mod manager, ModDrop!
We had a lot of trouble in the past with the people who worked on Torchleech, HotSpot, and HotSpot 2.0 all leaving mid-project, which I feel like kept us from properly competing with Steam's Workshop. However, not everyone uses Steam, and our new mod manager is pretty awesome, so if you found this thread years later via Google I hope you don't think the community is dead and the mods unsupported.
The mods are all still over at http://www.runicgamesfansite.com, where they've always been (so I hope this doesn't look like spam for posting it). If you have any questions hit me up at firstname.lastname@example.org and I'll do my best to answer promptly!