It seems to be more useful in the last patch, though that might be because of the massive -10% mass I've got on the pathfinder.
Must just be the pathfinder because the soldier gets very little boost from disc-jumping unless you already have momentum.
It feels like defense in general has gotten the shaft in T:A. Mines are a deployable and you can only carry two if you're playing a specific class and have the necessary perks, you can only carry two grenades total (if you have the perk), you can only carry two weapons total and have very limited options of weapons to choose from. Grenade-throwing is also a fully-committed animation that forces you to lower your weapon and there's a significant delay between the time you press the grenade key and when it is actually thrown.
The only change that benefits defense is the health regen and spawning with loadouts, but that doesn't really compensate for the lack of firepower and disc-jump boost.