The source interview section to the time stamp: https://youtu.be/4b_o5ueZRF0?si=IZzMan9sVQOV4Qq6&t=4797

Main short comings(for the parts I know and working with):

• There are many inter-connected features that works best if you use them together, so for example, if you want to use Lumen but don’t want to use Nanite you can, but the performance would be worse since the virtual texture part of rendering lumen scene is a lot more efficient when you use Nanite geo. Similar with VSM.
• If you upgrade project from old UE4, there is A LOT you need to touch on. It’s like a ticket generator if you upgrade.(but yeah, do a cross gen engine upgrade would do that for you.)
• TSR(their temporal super resolution upscaler) still not really working out of the box and most I know just use FSR/DLSS/XeSS
• many features are moving target BUT was talking point during recent releases. ie. PCG, Substrate, Smart Object, World Partition(specifically the Data Layer part), even VSM just out of beta since 5.2(most current released UE5 games using version <= 5.1, Immortals of Aveum would be the first to upgrade to 5.2 as far as I know.)
• because of the above point, the CVars to control features can be changed/deprecated when a new release goes out. So you can’t “decide” your quality presets if you are still banking on upgrades.

Let me talk about the 2 things you mentioned:

• networking, this part is actually the “better” side, it’s a bit harder cause since UE4.26 it gets a lot of Fortnite’s improvement into UE-main. So if you are doing shooter even with a lot of players it’s actually better than most other engine on the market. But if you want to do things like say, fighting game or decouple input/game thread for lower latency, or if you have your own “space ship battle” with custom physics body not a humanoid capsule. Then you have to implement your stuff.(by ref how CharacterMovementComponent is implemented.)
• Physics, many people talk shit about ChaosPhysics, while it might not be as good as some other current industry standards for single player game, it will change the landscape of multiplayer game once it’s performance is up to par. The reason is ChaosPhysics is designed with networking in mind. So, yeah, if your game is player interact destruction heavy(ie. big enough debris don’t disappear), you need a more expensive server to run. There are less physics based multiplayer game cause the old implementations are all “bad”. (just see what Battlefield or Halo has done for the past 2 decades, the slight desync and player/vehicle fly to the moon is staple of bad implementation.)

Sheer overhead. It’s not a general purpose game engine, it’s a hotrod FPS engine with all the visuals crankABLE to 11. But if you’re not pushing for the high end pc/console FPS, adapting it to your game’s flow and perf reqs can be challenging. And it’s not the easiest engine to develop AR/VR or other new tech on, requiring hyper optimization and throttling lot’s of the engine’s gorgeous visuals. It’ll be interesting to see where it goes from here though, unity has fucked themselves 8 ways from sunday on developer confidence and their own fragmented shit show outside the board room didn’t generate lots of confidence either.

I’m playing with godot a lot these days lol.