Are we going to see any changes to the Shield 4 & 5 skills? I personally think having a block that costs 20 energy is a little too much, especially when it's the only block in the game that requires you to be rooted in place for it. Maybe 12 or 10 instead? I still think 15 would be a little too on the high side. Hell, regular Legend heal skills that have a ~30 second cooldown only cost 5 energy, so I have no idea why Shield 5 should have such a high cost for a skill that's on a 25 sec cooldown? I think Envoy of Exuberance is okay, but I think it'd be cooler to have it be more like Chrono Shield 5, giving both healing & boon on both travel trips.
This next one more pertains to power revenant in general: I think (Unrelenting Assault) Sword 3's initial cast time is a little too long for it to be useful for reactive defense in any capacity. Way more often than not, I frequently find myself being hit by attacks that I meant to dodge when i'm within the last 1/4 of the 3/4-second cast time, before the skill finally goes off. Now I don't know if that's intended design, but regardless of whether or not it is, I genuinely don't think it feels very good to be like that. I personally think either 1) shortening the cast time to 1/2 second, or 2) keeping the cast time as is, but start applying evasion property on the moment that the character's animation leaps into the little mist rift graphic (i.e. on the last 1/4 of the cast time), would do plenty in the way of QoL for the soloing power rev. It would make it actually feel like something I can use for reactive defense, instead of just something i'd rather simply blow for DPS because the evasion takes too long to kick in.
On the topic of build viability and trade-offs between competing elite specs in endgame content (T4s/raiding): If you want Herald to be a possible Healer build pick in endgame PvE, I hope you're considering how much more efficiency Heal Renegade offers to the table in that regard; much easier, faster high might uptime than Herald (who has much slower buildup by comparison) via F2, and also more versatile alacrity uptime via F4. As it stands, the only advantage Herald has over Renegade here is its Protection and Fury uptimes (both of which can be more easily covered by a Ranger if needed). Herald should probably be capable of more overall healing than Renegade if its wants to be able to have an edge, and I have high hopes that the teased 'Elevated Compassion' trait will go a long way toward making up for that (as long as you don't give the trait some arbitrary 1-sec cooldown that cripples its efficacy >_>).
Also, are you considering having Facets give support to 10 Allied Targets up from 5? I don't think I need to explain just how much of a "boon" (:P) this would be for the spec.
Thank you for reading, and thank you for finally giving some love to such an underrated elite spec!