I enjoy PvE more and don't PvP much at all. Also you say it's my own limited definition of 'skill' well your own definition of 'complex patterns's is limited. All you need to do is ask yourself would heroics be hard if you did them as a single player. No. It's just hard to get 20 people to not be lazy. The most skillfull thing in WoW PvE is managing a raid group.
They would be relatively hard yes. Obviously a lot of mechanics a group based, but still it takes some time to learn the patterns and perform appropriately the entire encounter. I think the comparison to Dark souls is relatively accurate. Is Dark Souls hard? Meh, once you learn the fights, it's pretty easy. It's still enjoyable because before you reach the stage where it becomes easy, it's actually challenging, until everything clicks together. WoW as a single player game would be the same. Yes you'd beat everything much faster if it was solo because for every failure check, there would only be one player to check for them, instead of 10, 25, 40, whatever. To say it'd take no skill though, I don't know, it seems pretty stupid.
On the complex patterns, I guess most patterns are very simple and I didn't express that correctly, I should have said something more like the complexity from the multitude of simple patterns. Let's say in an encounter you have a ground effect that you have to get out of, say fire. This is a simple pattern. Fire is under you > move. Now let's say there's a pattern that's like, move away from the boss or move close to the boss. That's a simple pattern. If you have both at the same time however, it means you need to move out of the fire in a specific direction, not any way you like. Still simple though. Now let's say you have an aoe that forces you to get out of the raid. Now you have to get out of the fire(and not step into it), move away from the boss but at the same time move away from your group.
The patterns pile up like this, with varying degrees of complexity(not that complex though, the most complex ones tend to be "kite this shit" since the force you to do something for an extended period of time). You have to move out of the fire, while changing targets when something happens, while moving away or close to the boss, while moving away from the raid, while kiting some thing if you get targetted by it, while moving counterclockwise in the room. While performing your main job, which at this point is probably all muscle memory anyway(unless you're a healer, then it's whackamole with a bit of reading ahead to start heals appropriately). For 10minutes with single mistakes being wipes in general. Lots of simple patterns pile up, with semi random frequency, some come at exact times, some come after the cooldown is over but whenever the boss feels like doing it and they generally all have various timers and targetting concepts.
I don't know why you'd consider this type of gameplay devoid of skill. What exactly would you consider being a skill based game if that's the case and you're not gonna use the pvp card? I'm kinda curious what you'd consider difficult or that requires your skill from your own definition.
