Sorry for my previous jumbled comment. I'll try to clarify, and add an item or two that came up recently.
1. I like some of the less-played mods like Astral Sorcery, but my friends and I miss some of the more useful magic mods such as Ars Magica and Witchery. The current magical mods in the pack don't do a good job at adding magic to the direwolf20 pack.
2. Industrialcraft 2 feels outdated in this pack, and without a direct energy conversion between IC2 and Thermal Foundation power, this only gets worse. Some mods, like Advanced Generators, require IC2 components. I have had to re-invent electricity on this server and others just to make a few components before abandoning those machines. Since they changed the reactor fuel recipes, I find even less reason to have this mod with Advanced Generators, Thermal Foundation/Expansion/etc., Immersive engineering, and Extreme Reactors, which all include efficient, RF powered machines.
3. Most of the Immersive Engineering machines draw far too much power. For example, the Arc Furnace uses 256,000 RF to smelt one pulverized iron into one iron ingot, while Thermal Expansion redstone furnace, which is usually considered the benchmark electric furnace, uses only 1,400 RF. The arc furnace is a direct downgrade that should melt itself down after smelting two ingots. The config files confirm this, and the industrial squeezers and fermenters from Immersive Engineering also use too much power, along with the Excavator, which is by far the worst ore-miner in the pack. I like the aesthetics and realism of Immersive Engineering, but it needs to be changed for balance.
3.5. In addition to the previous machines, the IE diesel generator has an average efficiency, despite it's size and cost. It has roughly the same efficiency as the compression dynamo, but can't be modified. I love its look, but it isn't very useful despite its powerful output. The IE wires, with three voltages, are clearly meant for (to some extent) long-distance power, but their resistance is too high even with high voltage.
4. Some bees appear to be missing. When I saw that coal and oil (I was trying to do a fossil fuels challenge) could be made from bees, I tried to find out how to breed them, but realized that Infernal hives don't spawn in the game, and that many bee species weren't in JEI, although I could find some of them in crafting recipes for certain items like coal. I've always liked messing with bees, and would like to see them in a more useful form on this pack.
5. The Thermal Foundation materials for Tinker's construct aren't in this pack. It's not that big of a deal, but my friends and I like being able to make tools out of all sorts of weird metals.
5 flaws are very few. Overall, this pack was excellent and well optimized. I've made a few third-party packs, but I always admire the FTB packs, especially for how well optimized they are, which lets me run the server in the first place.
I know that the DW20 pack is based on the one in direwolf20's channel and that changing it might not work, but everyone on the server agreed that these would be useful changes. I made some of them in the server config files, and so far they only make the game better.