The current usefulness vs cost of some of these items is not viable on the trading posts.
For example, stat foods, wards, coatings, are so short in duration that with the lack of gold income is having folk very dependant on users of Life Staffs for healing, and armor for buffing.
For an extreme example, a Lifebloom Flower is so rare and hard to obtain for a Powerful Health Potion, which could be used in each fight at level 60. There is not enough to go around for the demand that is needed so that item is passed over by either using a Strong (downgrade) or an Infused potion (only useable at 60) instead. This means Tier 4 potions are not going to be available or worth the effort put into the creation of one.
For some big fights, like in the expeditions, you can use two potions over a course of a fight. That is an expensive undertaking unless the reward for the fight is scaled equally.
I suggest this;
Weapon Coatings act like gem slots. Permanent until replaced.
Foods, Resistance Tinctures, Wards, etc, have longer durations and keep the current cooldowns.
Healing, mana, focus, regeneration potions are able to be condensed with possibly other ingredients into higher tier potions. This will lessen the lack of movement in the Weak and Common potion tiers.
Allow higher-tier ingredients to be used for lower-tier items for a bonus effect on creations?