Sorry, been sick, so my proofreading isn't super lucid.
"World PvP environment caused by [flying] mounts" (not sure I left out the most important part) is referring just to how world PvP ends up greatly changed in feel and flow because of the ability to engage far more quickly--and, if one kills successfully, disengage with far less recourse. The same stuff I talked about earlier.
I do think it's still a "risk" in that if invested in one skill set, e.g., something that plays like an Objective Team Shooter, only to have it later pushed towards something radically different, e.g., something that plays like a 3rd-Party-Favored Battle Royale, you've gotten to know something that then has very little use after that shift. Of course, we could say the same for radical balancing patches in PvE in games with actual customization (multiple, very distinct builds available to a given class), so... /shrug.Anyways, flying/mounting itself is not so much a risk, but a feature of the open world setting. If people want a more controlled environment, that's what instanced pvp is for, and that's also where you get two willing parties ready to fight each other.
But yeah, BGs and arenas are right there and World PvP has never been a gameplay type/mode that the developers would sacrifice anything else for (a bit of a shame, imo, because I think it can be incredibly fun if not left quite so barebone), so it's ultimately fine.
There are reasons to lock flight, though, unless one can do with flight everything that can be done without it. That includes things like set pieces (imagine some of the killer views moving between plates your first time on the moon in Endwalker); enjoyable auxiliary movement systems like grappling hooks and gliders or, hell, catching a ride on giant flying monster; the dangers that world presents (absent in XIV, so I realize we have no such examples here) and diversity of those dangers' forms; etc. Immediately flight greatly reduces the depth available to zone design unless many careful considerations are taken into account.The answer to your question is that it is a game system. There is no reason for flight to be locked in the first place. You have flying mounts and they should not forget how to fly until some arbitrary requirements are met. But if we're going to have those requirements, they don't need to be stretched long enough for all zones to be available in an expansion. Pathfinder part 1 could unlock flying for the starting zones, then add forced safe landing as you approach a new zone until you unlock flying there via pathfinder part 2. (That's just an example using pathfinder like in Legion and BfA with the two-part system, though I think the system should still be changed.)
Again, for my part, I hate the idea of unlearning flight. My absolute preference has always been the likes of GW2, with distinct mounts, but also to have them persist as combat companions. In such a design, one can curtail the negative effects on zone depth of the unlimited and basically physics-less flight we see in XIV and WoW -- since those mounts do not have unlimited or basically physics-less movement. If your companion-mount consumes considerably more stamina when it has to get you up somewhere, too, then fun little auxiliary movement systems don't lose relevance, even if you may replace, say, gliders with just... your ever-available mount. It'd also adds a further risk element to combat, a potential emotional fixture, etc., etc. The only downside is that it constrains available mounts, since they ought to be unique to each other and must have their commensurate costs for power. Which is why you'd never see it in a game like XIV, where we have flying behemoths who move identically to chocobos.
If flying in open world content is like gearing in raids, does that mean that gears don't matter in open world content?
You cannot even use a mount in most raids. You spend almost half your time in daily open world loops, for better or worse, mounted. You are looking at mounts as worth the same amount despite wildly different contexts. There's merely pre-content (and you can teleport to where you begin your daily grind loop just as you can teleport / be summoned to a WoW raid instance), and in-content -- or, what merely gets you to that gameplay and what is part of that gameplay. One's mount is an in-content factor (part of the actual gameplay) in the open world.So flying does not replace gears. Again, flying is transportation. It is the difference between someone being summoned/teleported to a raid or going there manually. That is the closest parallel.
Improved mount speed accelerates a good half of all you do in the open world. Improved gear accelerates most of the other half, the time spent fighting rather than mounted (though, ofc, gathering and item-interactions are also a thing off mounts and are not affected by gear).
You get to said zone. You have 4 objectives. They will take you about 11 minutes of combat and 8 minutes of travel, total. That gear helps the 11 minutes does not cause literally more than doubling your speed (200% to 410% + avoiding dangers and ignoring topography) for the 8 minutes to be a non-factor. They both accelerate those processes.The content that you do in the open world still requires you to be grounded. That's where your gears will help you, not flying.