from the looks of the direction garry is taking it and the early renditions of the game browser it looks more like roblox if anything, with instead of there being servers each game is its own self contained gamemode with several sessions of it running at once
i would imagine server owners are 100% going to try and get around this and make seperate edits of gamemodes for their own server (eg: a custom prophunt gamemode for a single custom server, seperate from the default prophunt gamemode) but how well that'll work remains to be seen
its lame honestly, the concept of a roblox-style game for an older playerbase sounds cool but i wish it wasn't taking place within the "spiritual sucessor" to gmod. people love gmod BECAUSE one server can be so different from another- i could join one TTT server and it'd be completely vanilla with the default models and css weapons and then i could join another with 24/7 minecraft maps anime girl terrorist models and some custom cw2.0 edit with railguns
hl2rp and rp gamemodes in general are very unlikely to thrive in s&box unless the possible workaround i mentioned above actually works lol. rp gamemodes are designed in such a way that having a wide range of servers to choose from, each with their different communities, rulesets, addons, and intricacies is almost required for them to work.
imagine having matchmaking for hl2rp and if you disconnect you have to pray you get put into the same server again else all of your characters are lost lmfao
additionally this pretty much strips a very large "community" aspect from the game as with this system any communities pretty much can't exist because each gamemode is pretty much just the same session of the gamemode with no seperate servers for different communities with different addons configs
idk maybe all this has changed im getting this from some video i watched last year before s&box was even in closed beta
those models are so fucking ass lol