I think they need to implement another means of defense aside mines. Mines are so ultimately vital (and my choice defending weapon against blackhands, and all units for that matter). Methinks it might mix the game up nicely if they included another means of defense, and only one side got mines. Perhaps laser-tripped c4 or something. Imagine all entrances with either a GDI tan or Nod red beam going across all door entrances, where you KNOW they'll go off if you enter. Kinda like the ones in Half-Life. Those rocked! Defusing them is another thing... 
But on topic, like I said, mines are my choice weapon. They can't disarm them, and they can't get around them. It's a stealth stopper.
Multiple coordinated stealths with engi backup... oh brother..
(edited)
Maybe built-in building defenses like in tribes? Each building had a small cannon mounted inside that needed to be destroyed before you could do anything (without being killed in the process). They weren't terribly strong, but they could keep a group of invaders busy for at least 5-10 vital seconds
. We've all seen an enemy APC rush a building we're nowhere near and said to ourselves, "There isn't a da mn thing I can do and that building is dead......". Unless they all hit my mines at the same time
.
[ April 19, 2002: Message edited by: snakeoil ]