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This suggestion is only concerned with collectible ingredients not the amount or type of essences, and for THE MOST PART will stick with what can be acquired F2P. Although I have nothing against some collectibles from particular packs being used, this is just a beginning. These suggestions ignore Purified Dragonshard fragments as an unneccesary complication.
Furthermore, it is not the indivual enchantments that make an item overpowered or create the possiblity of inbalance in the game. Its the combination of enchantments, and sometimes the combination on the appropriate metal weapon. So they shouldn't have penalized the indivudual shard recipes (with enormous or over-the-top ingredients) but rather should have made the Shard of Potential recipes (over +8 or 10 maybe) contain these rare and costly ingredients and/or added a cost to imbueing any shards on special metal blanks. Shards of Potential were a brilliant idea to begin with and should be the lynch pin of the best Cannith Crafting has to offer.
Shards of Potential +10 = Small Eberron Dragonshard
Shards of Potential +11 = Small Eberron Dragonshard
Shards of Potential +12 = Medium Eberron Dragonshard
Shards of Potential +13 = Medium Eberron Dragonshard
Shards of Potential +14 = Large Eberron Dragonshard
Shards of Potential +15 = Large Eberron Dragonshard
Anytime someone crafts a shard onto a special metal blank these ingredients could be required:
Imbue On Silver = Silver Bowl
Imbue On Cold Iron = Polished Ore
Imbue On Flametouched Iron = Polished Ore
Imbue On Adamantine = Adamantine Ore
Imbue On Mithral = Moonstone
Using this method has the added benefit of not making the process of leveling your crafting skills insanely costly at the high levels where after 10.1 most of the recipes required the purified dragonshard fragment. But still making it harder and more costly to make the weapons that rival raid/epic gear.
Collectibles as an alternative to or in tandem with Soul gems. Not suggesting amount, just type.
Greater Aberration Bane = Planar Spoor
G Animal Bane = Cryptmoss Worm
G Chaotic Outsider Bane = Outsider Tokens
G Construct Bane = Adamantine Ore
G Dragon Bane = Dragon Relic
G Dwarf Bane = Lumps of Coal
G Elemental Bane = Elemental Ingots
G Elf Bane = Elf Relic or Ivory Scorpion Icons
G Evil Outsider Bane = Planar Talismans
G Giant Bane = Giant Relic or Amulets of the Archbishop
G Gnoll Bane = Antique Bronze Tokens
G Goblinoid Bane = Shamanic Totems
G Halfling Bane = Pale Creeper
G Human Bane = Intact Fingerbone
G Lawful Outsider Bane = Planar Talismans
G Magical Beast Bane = Cryptmoss Queen
G Monstrous Humanoid Bane = Swaying Mushroom Spore Pods
G Ooze Bane = Oceanic Sphere
G Orc Bane = Shamanic Totems
G Plant Bane = Lush Cryptmoss
G Reptilian Bane = Icons Of Khyber
G Vermin Bane = Headsman Beetle
G Undead Bane = Necromantic Gems
Holyburst = x# of Mark's of Favor + 1 Ritual Athame
These are just ideas... please reply to each section if possible with your own opinions on the subject.
/wall of text done.