I think the question was why soul swap was changed in 5.4 in the first place. For no apparent reason they made it extremely powerful. The stuff that's going on at protectors etc. wouldn't be possible without that change in 5.4
Snapshotting is one of those things that we cry about now and romanticize but prior to this expansion it has never presented a balance issue. Sure it was a good vs better skillcap (prior to T15/T16) but it wasn't a huge lifechanging gain. When you compare even from cata or T14 its not the kind of difference you see now in SoO. You easily can see what 300% to 500% from affdots between baseline and everything lines up perfectly moment? I kind of agree with the devs it wasn't as much skill as addon dependency combined with over the top trinkets/metagem/racials/etc...
When you combine the lack of mobility (a separate issue/discussion) I think the skillcap isn't going to be refreshing when your bboy weakaura reads 10, soulswapping between haunts/MG's, and praying to the RPPMGods as much as keeping uptime of things during high mobility fights the devs are fond of. I don't want boring raids, nor the Rube Goldberg cata demo setup...focusing on situational awareness to max uptime on a simpler rotation simply promotes a more well rounded type of skill.
As for races I think JV is pretty much on the mark depending on how they tune the undead proc. Had some IRL things take me away from the game but I'm simply not enthused about the state of warlocks going into WoD. Almost to the point I'm not sure I want to come back. If I do it will NOT be HC this time just with friends and no more killing myself to do everything, grind every rep, push push push, etc.
I know this isn't going to be a popular opinion, but still.
Snapshotting isn't fun. And more importantly, it isn't intuitive.
"Need to refresh corruption. Ah now my trinket procced, better refresh corruption. Ah now my other trinket procced and Dark Soul is ready, better refresh corruption".
There are other, better ways that skill could be added to affliction. Personally I'm not sad to see snapshotting go.
I agree, Snapshoot it's popular just because there's addons because without it's just hell for manage and other point it's affliction it's boring how it works today and Snap it's the only "thing" left.
So I think the main problem here it's not the removal of Snap but how affliction it's nowadays.