I think instead of ALL friendly players being blue, you should have your squad show up as green dots. I think this would increase more squad base team-play because you will know where they are more often than not. Sure you get the Hexagons but I think this would just really help at long range.
Also having a different shape and/or color for the squad leader on the HUD instead of the grey Hexagon would be awesome, this would suggest more of a "chain-of-command" or who maybe you should follow. I think this would significantly increase squad-play.