Wife wants to start playing the game, which makes me super happy. However, I know if she starts and gets overwhelmed she will drop it sort of quick.
She wants to be a healer, no negotiation. What healer is the least amount of buttons, binds, macros and confusion for eventual Raiding. She watched me raid and was blown away, so I know that is the goal… but she isn’t exatly “gud” at manual dexterity type of things… about as PC as I can say it…
Thoughts? I have never played a healer.
Congratulations on getting your wife’s interest! I hope it works out.
I don’t heal either, but when this question is asked, two things happen: 1. some healers all name their personal favorite healing spec and 2. Holy Priest is suggested by the rest.
The reason is not so much about number of buttons as about the mechanism of Holy: You See Damage; You Heal it. It is intuitively simple.
Other healing specs have a much greater anticipation-and-timing component. Some may be trying to prevent damage, so you have to time your spells to optimise that, or you may have to time HoTs so that they heal when needed, or you may have to move, or also do damage.
With Holy, it’s See Damage, Heal Damage.
But sometimes something in another spec just feels more right to newcomers, so who knows?
Don’t neglect the resources you have at max level to practice and set up bars and addons: Proving Grounds and Follower Dungeons.
Before you go into class, ask her a couple questions and decide together how you’re going to level. Don’t use a level boost and pop her into max level with all the buttons, that’s overwhelming for any class/spec. Is she going to quest at all? Are you leveling an alt with her and questing together? Leveling through dungeons? Are you tanking or DPS? If you’re going to level this mage, she might want to consider a shaman since it has a bit of extra armor. I’ve leveled my shaman as resto and of all the healing classes it’s the easiest (for me) to quest with. Disc priest isn’t that far behind and are basically invincible if you do it right, but it takes a bit more than shaman to do it right. If you’re leveling with a tank, then any healer is an option.
The biggest concern I have with recommending priest is that it only has one dps spec, and it’s one of the harder to play and has a very distinct playstyle people either love or hate. So, priest is a great choice if you only plan to heal. Two healing specs means you get to try out two very styles (one reactive and one proactive), and you get some protection from the ever shifting meta as it’s less likely both specs will suck at any given time. While discipline is one of the hardest healer specs to master, it’s honestly pretty easy to get started with and I find it one of the less overwhelming specs button-wise.
But, then we come back around to the dps thing. Mob ilvl scaling in current content makes doing world stuff on a healer incredibly punishing. (You never really gain kill power as you gear up, only survivability.) Which can get frustrating. So, whatever healer you play, it’s not a bad idea to have a dps spec you like. In that case, I’d recommend Shaman. It’s healing is fairly straitforward, and she’ll get to try out both ranged and melee dps. It does feel like it has a lot of keybinds, though. (And I say this as a druid main.)
Both excellent points!
I have the distinction of being the worst priest ever to attempt that class. In any spec. THE worst. No-one else comes close! 
So that gives me a bias, but even with that bias I think I’m safe in saying that Priestis a pretty poor solo questing experience - either Shadow or Disc.
This wouldn’t matter as much if you two are always questing together, but it is something to consider.
What you might try is go to YouTube and search for something like
“Dragonflight Holy Priest” and “Dragonflight Resto Shaman” - and maybe “Dragonflight Resto Druid” as what I might consider the next easiest healer, though probably more complicated than the other two, since anticipation and timing are more important.
Shaman certainly has a much better questing experience,
And it would give her some small idea what the various options are like.