Why no classic mode in multiplayer?

I’m just wondering why are there no game modes where you just play with pre-determined classes? They said there would be many like that in the vidocs.

Slayer pro is the closest thing you have right now until 343 updates the playlists.

Adding onto the classic mode questions I keep hearing that none of the weapons have pre-placed weapon spawns, they’re empty. Is this true?
If so I would expect a classic mode to incorporate appropriate map layouts.