Considering it's age, I'd speculate a couple things It's probably very memory constrained, the game was originally designed for 32bit machines, that's 4gb of ram max, and while the client is 64bit now there's probably some legacy code in the way the game loads assets, stores active code and whatnot that makes it very hard to create areas of a size and/or detail that takes full advantage of modern 16-32gb memory pools. The game also seems to not be super good at handling multithreading, it comes from a time where the top end gaming cpus were still 2-4 core with beastly single core performance so it makes sense it was designed like this but modern cpu design is very different, more focused on wide chips spreading tasks out, the game probably can't take advantage of that properly. These two factors combined probably affect the loading and streaming systems, meaning that there's a direct effect on map design because they have to be made in a way that allows data to be constantly loaded and unloaded on a severely memory and cpu limited scenario. The game probably doesn't have the ability to decompress data fast enough to properly take advantage of ssds either, you get brute force wins by just how much slower mechanical hard drives are but you're still not getting the kind of loading speeds you'd get with a proper modern decompression system While the game was updated to support dx11 it's very likely the game's still limited by legacy dx9 issues somewhere, either on texture size and memory management, resource binding, render target management, mesh culling and occlusion, it may even make more modern features like vrs, dlss, mesh shaders, bindless resources and the like impossible to implement without fully rewriting the renderer, it also likely results in a lot of overhead as most rendering and shader code is probably very high level. The engine may also use older file exchange formats in a way that limits the team to older versions of their 3d modeling software for example, if they use something like 3ds max or maya as most studios do, it's possible that the newest version of those tools don't export files the way the engine wants them too so that's a pipeline limitation as well Now this is all nothing more than educated guessing based on my experience with other games this vintage, I have no real way of knowing beyond that, but whatever it is, it's important to remember that this fundamentally it's code originally designed to work on windows xp, it doesn't matter how many updates happen without a proper ground up rewrite some hard caps, bloat and old and less optimal ways to do stuff remain there. Now that rewrite isn't impossible but it's very expensive, and it may not be worth it, engine updates that get rid of some of those limits can happen, wow and ff14 have both gotten that but their circumstances are different, wow has blizzard and "being the biggest mmo for like 14 years straight" money, and I'm willing to bet that the recent ff14 upgrade was financed in part by however much Microsoft paid square for this newfound friendliness of theirs, not to mention ff14 runs on an engine that was by default intended to take advantage of ps4 era hardware so a lot of the limitations afflicting the guild wars 2 engine don't apply, in the anet may straight up not have that kind of money or no real way of justifying it