It would be nice to have some kind of usable trains/metros for immersion purposes.
But, let's imagine that there are trains/metros that aren't usable regularly, but used only in quests like:
I) Chasing an assassin that disappeared inside a populated train, and you have to follow the guy to find out who he work to inside the wagon, when you're almost approaching him, he break the window, while leaving some explosive, which explodes and causes a massive accident - you survive from pure luck;
II) A frustrated corpo go wild, capture one of the train wagon that belongs to Militech, and Arasaka contacts you to, so you could either go with the corpo and split the share, give it to Militech or sell it to Arasaka (kiling or sparing the corpo in the process);
III) A car chase that started on the streets end up with the shooter taking a train and you following him with your car, while firing weapons, which leaves the train heavily damaged;
IV) A valuable cargo that is going outside Night City have to pass through Nomad territories, so some corpo guy hires you to protect it, then you can either betray the corpo, let it be stolen by the nomads while killing other mercenaries, or killing the nomads, protecting the train and gain some reward.
Now, we have to consider how the city would react according to CDPR vision of the game: did they implemented the RDR 2 system? Could you steal, burn, destroy the metro/train, and in the next day (or just some time after the incident) they would keep respawning like nothing happened?
Because if CDPR didn't use the RDR "respawn as nothing happened" mechanic when it comes to huge accidents like that, then after the first one, the train/metro would be left unusable because the authorities could be investigating the crime, or because it would be being fixed, who knows?
We have to remember that this is not a sandbox, it's RPG. Actions, specially big actions, are supposed to matter in the world context.
As for the trains/Metro, if we presume that there are other methods of fast traveling, and the trains/metro are linked to specific quests, there's no practical reason for them to be essential in the game. I understand that instead of doing it (now), they should address things more critical for gameplay purposes.
What I mean is that there are bigger problems (my opinion) to adress now (that I wish to see in future DLCs):
A) Car upgrading and customization, because racing is a thing in the game. It's a piece of the street culture showed in Cyberpunk 2077, so there are a lot of possible contacts and missions that could be linked to street racing, like gathering info about what's happening on the streets, things like that.
B) Multiple houses/apartments and customizable ones, so the player can connect more with the place that was customized with hard (dis)honest mercenary money. Maybe with more than one place, it could be a quest where people try to kill you by blowing your place, then because you survive, it opens the option to seek revenge, let it slide by faking your death and going to live somewhere else, and fix your first house later while living in the second one.
I bet that when CDPR showed the Metro/Train, they meant to show V as a newcomer to Night City, as we all were (and still are) in 2018, not to put it in the game. Probably they didn't even imagine that there would be a lot of fans asking for it.
But, for now, the lack of usable trains/metros doesn't really affect me.
