I'd still keep Surecast and Esuna, even if content doesn't demand it that often, they're still useful abilities unlike Repose and don't have the issues that Rescue entails. I also don't need Benediction 90% of the time, but I still count it as part of the WHM kit. We still count Rampart and Provoke as essential parts of the tank kit alongside Shirk, even if Shirk sees less use outside raids.
I can agree with the criticisms over a buff/cooldown, in that we're still doing primarily Glare casts, but the main thing really is to bring something that breaks the Glare monotony, so a 15s buff/cooldown with a 21s DoT + a Super Glare every 3 Glare casts can be enough. If that cooldown also unlocks the Super Glare by giving the extra stacks or by removing the Super Glare cost, then it further adds to that engagement of the kit. WHM doesn't need much to be engaging, have lilies offer more interesting heal options apart from Afflatus Cure II and Afflatus Medica (at least put some Regens under the lily system Square), and you have a simple kit that has at least 4 things to watch out for (Super Glare stacks, buff/cooldown, DoT, Lilies). Add some longer cast times and now we're adding elements of good positioning, weave window creation, and the resource management required to make those things to watch out for too, unlike always having the 1.5s cast times we have now. An example would be having that cooldown with 2 charges (I'm thinking of it being an instant cast GCD cooldown ala Sonic Break) and it's now a movement/weave tool as well as a Super Glare charger and a cooldown to keep rolling.
It's super simple and so long as Square makes the GCD heals an actual part of the kit, we can cut out oGCDs (which is part of what makes the nuke spam so dull, oGCDs just let you nuke more) and the kit may actually have some meat to it. It's also worth remembering people were happy with healers back in SB where we didn't actually have a huge DPS kit; WHM had 2 DoTs with the longest being 18s long, SCH had 3 DoTs (4 with Shadowflare on a 60s cooldown, and Miasma II was more movement/weave tool than a maintainable DoT) and Bane was only useful in dungeons, AST had the Nuke + DoT we had now but more interesting cards. We legitimately don't need much to make healer DPS engaging.