For instance, in the original Age of Wonders (turn-based strategy game), the short descriptions given for every unit with an often great piece of artwork along with it. Many of them were not particularly original, but still they were fun to read, and the loss of those in the sequel AoW II (along with changes in graphics, obviously) made that game lose a lot of the charm of its predecessor - even if the game mechanics and gameplay possibilities were a good bit better.

In Age of Empires II (yes, can you tell that most of my games are way old?), the expansion added a farming queue of up to fifteen farms, keeping you from having to spend half of your time rebuilding exhausted farms instead of focusing on the unit production and fighting. I'm really not quite sure how people managed to play big battles before that.

In Torchlight, there are a few features which are notably - and intentionally - lacking from Diablo II, making it a lot less frustrating than Diablo II. The way dying is handled and town portals that stay open when you close the game come to mind, but the big one is transferring items between characters. The amount of times I've found gear in Diablo II that would be awesome for another character but all but useless for the one who actually found it... Of course I get that the game would be significantly easier with that feature, but really, it takes so much time already to get a character into the higher levels where the game is really fun, and it's not as if you find unique or other good gear so often. Frustrating if you then find something you would've preferred to find with another character.

Though Diablo II does have a very cleverly thought out system in terms of replayability, difficulty level and how you save - you can save and quit at any time, but only at certain places can you save and continue playing from the same spot.