Ars Magica, if/when it's included, has one ore, I believe, and has a few buildings and dungeons it sprinkles about. Tropicraft, if/when it's included, has pineapples and palm trees, and maybe some bamboo. Those are the only two I'm aware of that might be added and have any world gen stuff. If you don't plan on making use of either of them, or you have no qualms using Mystcraft for the Ars Magica strutures and Tropicraft plants, then I don't think you're going to run into much of a problem using the Mindcrack pack. The Direwolf pack is missing GregTech ore generation.