So I tried out Torchlight, mostly on the advice of Tycho and Metacritic. Here are my thoughts so far.
Diablo I was a great game--it broke a lot of ground. It was mentally light, but very addicting, and very replayable. In many ways Diablo II was a different game. It got a lot more complex, a lot longer, and a lot more involved. It has a much larger complexity profile. It also made some big improvements on the first game in terms of usability, balance, etc., but for the purposes of this review, consider that Diablo I and Diablo II are two different games.
Think of Torchlight as Diablo I, with every rough corner removed. When you launch the game you can pick up your progress within 10 seconds. Everything is streamlined. Anything that was annoying about Diablo I has been removed, and some modern tropes like WoW-style skill trees have been added.
Torchlight is a fantastic single player hack-and-slash dungeon crawl. It is 60% loot, 35% character progression, 5% story, and 0% bullshit. The graphics are simple but really well done. The gameplay feels really good. It doesn't break a lot of new ground, it just does what it does perfectly. Torchlight is the new reference Diablo I experience. And it's a great place to park your brain for a few minutes (hours) when you don't feel up to a more complex or social game.