Rifleman's minning speed is also a problem. It requires almost three times the installation time of mines from other factions. It is a heavy penalty that the core combat unit, which is not an engineer, is tied to the landmine installation for such a long time.
+1 I was going to suggest buffing the Field Defenses mine laying speed for Heavy Calvary and Infantry company. You very rarely see people making use of this ability because of how long it takes. Otherwise FINALLY fixing the M20's insane MP cost would help out at lot as well- right now it just doesn't make since to invest in a unit that has a very short shock value window just to lay mines. I can't remember the last time I've seen a M20 let alone the Mines.