He sees limitless potential in S&Box, and wants it to succeed, predicting that it could permanently change the gaming landscape. And believes it could be the best game engine.

His main issues, concerns and suggestions are

It's a bi-polar game. Attempting to be a game engine to create standalone games, but also trying to be a roblox like game platform which incentivizes slop games meant for engagement farming
Most games might as well be flash games on addictingamesdotcom
Updates break things constantly with no docs on how to update code
The docs are awful and even non-existent in some cases. As well as de-loading if internet connection goes out.
No docs on how to update code (He had scour through update blogs to figure out why his mod was broken, it was a shaders update, and reverse engineer it to fix his code)
S&Box needs a team of technical experts to make well understood docs and tutorials
Everyone says to just go to discord on the forum
No standardization, so everyone has to make things from scratch - have to make even doors from scratch
And because there's no standardization, every game requires GB's of downloading
The game competition idea will favor teams of developers over solo devs
Has that uncanny fake look to it somewhat like unity games - and no unified art style - Everything looks flat (But this last point is a problem with Source 2 in general)
Scenes are a nightmare
Microtransactions that are pointless because they can just be free assets put into games
S&Box needs it's own IDE instead of requiring a third party IDE like Visual Studio which is filled with bloat

Drop trying to become a Roblox killer. And dedicate everything to become the best game engine, and monetize via an asset store.