Update 21.2 is on Bullroarer and will go live soon. Among other things, it will add new armour and jewellery available for barter from allegiances, and new craftable essences to put in them.
Current allegiance gear is item level 326. Most of it is Rare/Purple for 25 Tokens of Service and a few Teal/Incomparable pieces are 75 Tokens of Service.
A new 1000 unit allegiance rep token will be used as the barter token. Allegiance quests will now reward 2 of those instead of a 2000 unit token. The 5000 and 10000 unit tokens will be exchangeable for 5 and 10 of the 1000 unit tokens, respectively. So far, there is no exchange for the 2000 unit tokens you might already have.
The new jewellery will be item level 330, but otherwise seems to follow the same pattern as the current allegiance gear. Most of it will be Rare/Purple for 50 of the 1000 unit rep tokens, and Teal/Incomparable for 100 of the 1000 unit rep tokens.
The new armour will be item level 330, but otherwise seems to follow the same pattern as the current allegiance gear. Most of it will be Rare/Purple for 65 of the 1000 unit rep tokens, and Teal/Incomparable for 130 of the 1000 unit rep tokens.
There are craftable Tier 10 essences, which require level 115 gear (Tier 9 needed only 106). Crafting them uses a Universal Solvent and a quality item, but is a permanent (not single-use) recipe, so you can make them easily. The Empowered Shadowed Esssence is a box like the Shadowed Essence and is not bound, so can be passed, sold or traded. Empowered Shadowed essences are about 5% higher than Shadowed essences.
There are two new instances that I have not investigated that will presumably drop gear. They also will drop tokens that can be bartered for item level 330 shields and off-hand weapons.
As always with information from Bullroarer, this is subject to change.