You absolutely can do Prey with WM on. Is it advisable? Depends on how active things are in your realm. You will find it hard to survive a hard mode ambush while pvping imo (not that the NPC is that dangerous but it is dangerous enough to allow the enemy player to kill you). And in hard mode every death reduces prey progression (in nightmare it resets it).
as a PVE it's really just another WQ with some extra steps/flying around. Does not hurt but it's also nothing to write home about (so far?)
I wish I had spent this expansion adventuring with Astalor instead of Arator. Astalor is way cooler. This guy is the only true Blood Elf in this entire expansion. He's not your friend. He is not a hero. He wants to rip anguish out of the souls of anyone he thinks he can get away with. He gives no hoots. It's nice to have something like Wrathion from MoP again where you get to work for a dubious guy. His voice actor, Jason Marnocha, does a great job. Awesome characters like these need to be who you spend the main campaign adventuring with.
It's a shame that the Prey targets are unvoiced, though. From the quest description and Astalor's remarks about them, they sound like neat villains.
The Prey targets themselves were not really a problem. The only difficulty I faced was when I was doing world quests in an area filled with HP spongey elites that you can't burst down. So getting ambushed by a Prey target feels stressful, and I had to run away or scrap by the skin of my teeth a few times. I was level 89 and undergeared, but I was playing a Death Knight with strong survival capability with Death Strike. So it'll probably be a lot easier with my last Apex talent and gear ready for the normal raid. Though there is apparently a hard and a nightmare difficulty. I wonder how rough those will be for other classes.
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For normal difficulty, you are only threatened if you are 1. undergeared and underlevelled, and/or 2. go to an elite area and pull at least two elites. Otherwise, the prey mobs aren't scary and them showing up is just whatever.
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I never understood how the Worldsoul echo stuff in TWW worked or was supposed to work. I looted a quest item (somehow), got a quest to go to a beach on the Isle of Dorn to release it, then some enemies spawned and I killed them, and then... ???. The scenario didn't progress or complete. I wasn't sure if it was a bug or if it was a miscommunication or what.
Whereas with Prey, the only miscommunication I had was completing the quest to unlock the prey feature and then flying away from Silvermoon, not realizing that I had to click the table to then start a prey hunt.
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It does feel ridiculous. It is also odd how I am zooming around on a dragon at high speed to different world quest areas, and then the Prey villain ambushes me on foot. As if they had somehow ran across the zone on foot at mach speed to catch up with me.
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It would be nice if they hadn't abandoned dragonriding races. That was very engaging content to do out in the world.
My biggest worry is that other people being unable to help you on higher difficulties will make it more tedious, if it always boils down to a solo duel. No emergent gameplay here to shake things up.
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It might make more sense if for each ambush, you made visible progress towards the defeat of the villain. Ie, the gnome girl comes in one a mech, and with each ambush you break off a body part off of the mech, until the final confrontation in which it is smoking and barely operational, and then kill her. Rather than what feels like you having half a dozen samey pointless fights.
So far, pretty much, yeah. I think eventually one has to decide, if the cosmetics are worth it, as gear seems to go only up to Champion track. Apparently this goes all the way up to Nightmare III. Nightmare itself is unlocked on March 17th, no idea how to step it up from I to II and then III.
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Also better visible progress on the icon would be nice. Just put a % number in for example.
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Odd take. No content is for everyone and you can pick and chose where you put your priorities. Prey is not for you. Great. PvP is not for me. So what...I just don't do it. I will miss out on some nice stuff, but that is a trade off I am willing to make.
Having now done a couple of them, including graduating to some of the Hard mode Prey, I've got to say that while not mindblowing, it definitely adds an element of difficulty and suspense to doing WQs and other overworld content. Prey targets seem to love to ambush you while you're busy with other mobs, and I had several pop-up when fighting rares or taking out multiple mobs to complete a quest. While I think it is likely to be one of those systems I max out and don't touch again, unless it offers new/improved rewards, it is pretty fun and adds more to do outside of dungeons, raids, and delves.
"We're more of the love, blood, and rhetoric school. Well, we can do you blood and love without the rhetoric, and we can do you blood and rhetoric without the love, and we can do you all three concurrent or consecutive. But we can't give you love and rhetoric without the blood. Blood is compulsory. They're all blood, you see." ― Tom Stoppard, Rosencrantz and Guildenstern are Dead

It does a decent job at spicing up world content definitely seems like something they can build on.