I don`t see much room for consolidating our spells without fucking us up in points of flexibility and I don`t even want to start about dumbing down to be playable by braindeads ...
Let`s start with the basics:
Merging Cures? Would be pointless on any healer class.
Some effect occurs ...omg I press one damn button and it`s countered and I don`t even need to think about which of those effects is worth more curing first. Reminds me of some stupid as heck retarded games I played back when I was 4 years old.
Merging some of our Heals? I can`t see the benefit.
Upgrading reactives with a heals on expiration and so on are fundamental changes I`m sure won`t come and I don`t either want to lose my group heal for such functionality.
So it`s all down to a minority of our spells that are even worth merging without kicking us completely in our face:
Merging Pious with Fanatics would be nice if it was for one and not two conc slots. Taking away flexibility from us is always bad. More then often do I run with 4 or 5 Consecrated as many of us do and fill the empty conc slot depending on the situation. Combining those 2 buffs for a cost of 1 concentration would be a nice upgrade.
Act of Conviction could stay alone but there`s the idea of merging it with a groupwide consecrated aura for the cost of 3 or 4 conc

(would kill most of the buffing time)
Forced Obedience is encounterwide and should stay alone or merge it with an encounterwide Convict.
Debase + Convict is fine for me as long as I am still able to debuff more than one target with convict at a time.
Affliction + Absolving Flames would make sense, but takes away chances for procs. The melee way could stay the more flexible with those still as 2 attacks on their own. If it`s that way round I don`t really care.
Ruthless + Litany ... no way, one`s single target, the other encounterwide and it would be even more bad merging the melee styles of those two, because there are situations you need everything but heck no open AE to fuck everything up.
Vengeance + Compelled I don`t care for. Can`t remember when those 2 did what they should do all the time and where really worth power/casting-time ... that tool is broken.
Seems I`m not that happy about SOE merging anything on us

On most classes to only think of merging abilities is like opening
Pandora's Box.