The "problem" with remote mines was that you could throw a mine and press A+B at the same time while it was still in mid-air. BOOM! Instant detonation! So you'd be able to just insta-kill people who weren't expecting it.

Eventually it balanced out because everyone would be a lot more careful about getting close and going around corners, but ... let's just say that raegquits are a lot more fun in-person :)