I admit that the central area (B flag in conquest) has some issues. But all other areas were super fine. Rush on Metro with lower player numbers was super fun.
The map was just not made for 64 players playing conquest.
But that is sadly all for what the map is known for in the end because people used it to grind their stuff. It can be an awesome Map with the right game mode and settings.
Edit: yes it's very possible to compare metro with bc2 maps.
BC2 had awesome maps made for rush. The best Rush maps in the franchise. But you can't have everything. Most of them suck in conquest.
In BF3 they made every map for everything and that just didn't work very well. So some maps were just good in Rush (Metro, Damavand peak) and others only in conquest (Caspian border is my fav map but it was sooooo bad in rush...)