Honestly, I'm actually inclined to agree with him on this one and since 6.1 I've thought it myself as well.
WHM doesn't have much, but one thing it does have over the other jobs is a little more broad synergy within it's kit coupled with a slower but consistent rhythm, it's historically usually felt more impactful and direct than it's alternatives as well (Even if the numbers generally don't reflect that). The Lily System is easily the best healer gauge mechanic of the 4 now, it has impactful self buffs and Assize is literally a second charge away from being perfection, it's this sort of thing that SE need to build upon.
As far as the suggested WHM changes go:
The return of Aero III or a renamed version of it is gud, I'd go one step further and also return Fluid Aura with some potency as an oGCD on a 30 second timer.
As mentioned above, IMHO no WHM adjustment suggestion is complete without adding a second charge to Assize, I've mathed out why it's such a huge benefit to the ability with zero downsides and it just makes sense at all and every level. It allows it to be aligned and double cast with bursts window whilst also giving you a free charge to actually use as a heal in between. Everyone wins.
Personally, as far as the Glare combo goes, my take on this is slightly different. I'd actually like to see a PvP style auto combo that breaks on any other GCD action with the second and third steps having an increasing chance to proc a secondary oGCD alongside reducing the cooldown of your Thorns ability.
This adds some nuance with a proc to watch and rapidly reducing cooldown to track whilst also visibly rewarding and encouraging consistent DPS and the prioritisation of oGCDs to keep it going.