I thought I would flesh out my earlier criticism with some constructive feedback about my opinion of what Departed should be. I may add additional ideas to this post in the future.
The title of the modpack invokes an exploration theme, that the player will be going on a journey; within the context of Minecraft mod pack categorization, I believe it should be an exploration modpack first and foremost. So, going through the current Departed mod list, here is what I think should stay and what should go. Please note that my judgement of a mod in this instance has nothing to do with my feeling about the quality of the mod or the experience it provides, only it's appropriateness for this particular modpack:
Forge/FML by LexManos, cpw = required
Advent of Ascension by Xolova = required
AppleCore by squeek502 = remove
Aroma1997Core by Aroma1997 = keep
AromaBackup by Aroma1997 = keep
Baubles by Azanor = remove
BiblioCraft by Nuchaz = ambivalent, aside from decoration and some minor block utility, it does allow you to copy enchanted books.
Botania by Vazkii = remove. While it does have a bit of exploration built into the progression (gathering flowers) its very minor and short lived in my experience.
bspkrsCore by bspkrs = required
Carpenter's Blocks by Mineshopper = keep
ChickenChunks by Chickenbones = ambivalent, does not really matter
Chisel by AUTOMATIC_MAIDEN = keep
CodeChickenCore by Chickenbones = keep if retaining dependent mods
CodeChickenLib by Chickenbones = keep if retaining dependent mods
Custom Main Menu by lumien231 = keep
DecoCraft by RazzleberryFox = keep
Dr. Cyano's Lootable Bodies by DrCyano = probably should keep, since if I recall correctly it addressed an issue within AoA that may or may not be fixed in future AoA releases.
Enchiridion by joshie = keep
EnderStorage by Chickenbones = ambivalent, certainly convenient
ExtraTiC by Glassmaker = remove
FastCraft by Player = keep
FastLeafDecay by Olafski = ambivalent
Hardcore Ender Expansion by chylex = keep
HarvestCraft by MatrexsVigil, Rhodox = if Spice of Life is retained, keep, if not, ambivalent
Iguana Tweaks for Tinker's Construct by boni, iguana_man = remove
Inventory Tweaks by Kobata = keep
IronChests by cpw = ambivalent
JABBA by ProfMobius = ambivalent
JourneyMap by techbrew = ambivalent with a lean to remove (the radar is my main sticking point, especially with AoA invisible mobs)
Mantle by mDiyo, progwml6 = remove if no dependencies
MineTweaker by StanH = depends on if you need it or not
ModTweaker by jaredlll8, joshiejack, SpitefulFox, Yulife = depends on if you need it or not
NEI Addons by bdew = depends on if you need it or not after removal of other mods
Not Enough Items by Chickenbones = keep
Not Enough Keys by Mr_okushama = ambivalent, may no longer require it, but does not hurt anything.
OpenBlocks by Mikeemoo = ambivalent
OpenModsLib by Mikeemoo = retain if necessary
Redstone Paste Mod by FyberOptic = ambivalent
Resource Loader by lumien231 = keep
StartingInventory by bspkrs = keep
Steve's Workshop by Vswe = ambivalent, but really does not hurt anything
Thaumcraft by Azanor = remove; it also has an exploration component to progression, including a small dimension, but again its relatively minor and short lived.
Thaumic Tinkerer by pixlepix, nekosune, vazkii = remove
The Spice of Life by squeek502 = ambivalent; depends on the pack it is in, in Departed it is annoying since I believe it needs Hunger Overhaul and proper configurations to have meaning beyond annoyance, and that only happens within the context of a "hardcore" mod pack. I do not think Departed is meant to be hardcore. It could be, if desired, but from the feedback on the forums, I see many players saying the AoA mobs are hard enough for them.
TiC Tooltips by squeek502 = remove
Tinker's Construct by boni, mDiyo = remove
Translocators by Chickenbones = ambivalent
Waila by ProfMobius = keep
Wawla by Darkhax = keep
Witchery by Emoniph = remove. It does add the spirit world, but like the other magic mods, its mainly a gate for gathering certain required resources for progression.
Ztones by riciJak = keep if only for the decorative options.
If you remove anything at all, I would remove ExtraTic, IguanaTweaks and Tinkers in that order. Other than the often discussed issues with Tinkers crossbows, several of the AoA armors require ingots from mined ore, and Tinkers ore doubling of AoA ores through ExtraTic makes things a bit easier than it is probably intended in AoA. I also recall from the announcement livestream it was mentioned that Xolova was concerned with mods adding flight mechanics breaking some of his content, which is why XU was omitted, but flight is still possible via Botania, Thaumcraft and Witchery.
If you want to keep one of the big three magic mods for utility sake, keep Witchery with the broomstick disabled, as I feel it provides the most utility without stepping on AoA progression.
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With that said, what would I add? Probably other dimension mods (DivineRPG, Erebus, etc.). Perhaps some overworld exploration content mods (Ruins, ChocolateQuest, etc.).
You may consider forcing progression through a certain dimension order with Minetweaker/Modtweaker if possible, but it is not necessary.