G4b sounds like a security firm 
shooters usually come with map editors, if they want to survive longer. this ensures more maps overall. as i already stated (we are going in circles here), some stuff cannot be procedurally generated that well.
in an abstract sense, minecraft is a shooter, which allows you to change your map.
you can see that e.g. with 7 days to die or rust… or cube…
and there are a lot of procedural generated games in the coming, some of them are clearly focused on being shooters;
it may be true what you say for a developer, but not a game designer; you either are an artist, or you are not; does not make you worse in working on games, sometimes you need both elements to be successful; but the artist would rather starve than not try to get all his ideas into a game, including “randomness”. sometimes not all of these ideas are even good ideas.
That’s the problem when we let the players chose their “battlefields” in PVP games, they will usually pick the ones they like and are more familiar with; at some points only a few of them are used, even if many exists and people creates more of them. The more competitive you are, the less randomness you want besides the other players. It’s a shame though, i wish there was at least one game that bothered to make procedural arenas, or at least have several variant of the same map so you are left guessing how to play it.
Games that have procedural maps right now are usually those with strategic elements or when PVP isn’t an issue (ie coop or solo play).