I find classes with downtime and low APM more enjoyable to play with.
In other words - being precise with ability usage/rotation over pressing available buttons.
What would be your recommended classes/specs in each role (tanking/healing/dmg)?
Again, I’m not asking for the easiest specs, but for low APM and precision.
(Just in case:
APM - Action Per Minute,
Downtime - Time without ability usage during combat).
EDIT:
Data provided by others
On my bear I legit macro’d his entire tanking rotation onto 1 button on my Logitech MMO mouse.
I cannot post links, but this is the data from Simulationcraft:
Arcane mage at 34 APM
Warlock Afflicition Necrolord at 38
Druid feral at 43
Highest is:
Prot warrior at 81
Fury warrior Necrolord at 74
Fury Warrior Kyrion at 74
Kyrian Arcane mage is probably the lowest all around.
Affliction and feral are both relatively low.
Also Marksman Hunter, I average about 30 APM for each key, and 35 APM for bosses.
http://www.simulationcraft.org/reports/T28_Raid.html
That’s from simcraft, keep in mind they have MM as a troll which adds another haste CD and more APM. If you aren’t a troll or don’t use that haste CD well you won’t reach that high of APM.
Interesting. I figured WW monk would be close to the bottom of the APM list
Update: Ah, I found it. 49 apm
Well, immediately it seems like you’re more fitted to a caster.
Depends on your build and the content type. It can either be a spec where you can fall asleep “behind the wheel”, or can’t keep up.
I actually think Destro has a much lower APM.
i’d say probably DH as the lowest APM…druid has some of the higher apm specs for sure 
What do we think about Arms Warrior or Unholy DK?
I have an Unholy DK, and as much as I love it, I usually have to take a break because my wrist / hand hurts after like an hour of “actually” playing (like a M+ or arena).
It isn’t necessarily high APM that makes my hand hurt, it’s the fact that I’m spamming the
same 1 or 2 binds over and over. For example in AOE there’s a spell called Epidemic that you’ll spam, but because this isn’t part of the ST rotation it isn’t on a super comfortable bind (such as 1 - 5).
To me, this statement is not DK.
I don’t play Arms to give you much insight to it, but I recall it being a fairly sluggish spec.
You are confusing number of abilities with frequency of actions. DH has low number of abilities, but is quite high for both specializations in frequency of actions.
Necro aff is dragged down by having to do the full drain soul channels. Destro doesn’t have anything that’s close to a 5 sec cast, plus stacks all the haste.
for once this is something i have a little experience with. You’re right - I think frequency of action does matter… but i still think DH’s kit is very low apm…i played a rogue for a few years, and I have to say just having more abilities does actually contribute to APM. Big time.
idk DH just feels really slow to me, but then again, I play druid now so idk.
http://www.simulationcraft.org/reports/T28_Raid.html
From simcraft APM by spec under the additional details tab. Including a few specific covenant variations of specs. Both DH specializations are in the top quarter and above all Druid specializations.
Obviously this is based on a specific build case, but DH’s will always be pretty fast due to their built in passives. Druids also are fairly fast with the exception of feral.
Generally Frost Mage is pretty slow, as is Assassination.
i honestly thought you were talking about PvP this entire time. I am gonna just say, raid healing isn’t anything like PvP or M+ healing.
I would fully expect a DPS DH to have more APM than a resto druid staying in one form the entire time for a raid encounter.
But I play a DH sometimes, and it’s a really simple class with very few buttons. A Resto druid or Resto shaman is using almost all of their abilities in a M+ key, or suviving an arena match…i don’t think you can even compare but if you have numbers, I’m def open minded to be proven wrong here 
Neither of those are slow in Shadowlands. Although Assassination isn’t necessarily on the crazy fast end depending on build.
Frost mages primary CD is a 30% haste buff. Also the best lego for frost mage is one that stacks up cast time reduction on frost bolt. Add to that Frost values haste as the 2nd best secondary and frost is high APM.
WW monk is one of the lowest but I 100% guarantee you will not enjoy the spec.
So this is my 244 Arms warrior doing a 15 mists with 0% haste.
https://www.warcraftlogs.com/reports/9wBak8PvKQxmjpcA#fight=2&type=damage-done
And this is a summary of casts per minute, which is essentially APM:
https://www.warcraftlogs.com/reports/9wBak8PvKQxmjpcA#fight=2&type=casts&source=5
With more haste APM will go up, significantly.
as an RTS player, I appreciate this. No idea this was even a thing til now. 
Well I’m basing my points off of the simcraft information as well as my personal experience. I try to make builds work for M+ with as low haste as I can manage. DH has always felt too fast for me, but I have never played one enough at max level to really compare it well.