I used to equip soldiers with a combat knife very early on when I first started playing. One guy even got a kill with it once.
Later I moved on to using machine pistols as back-up weapons for the troops. The other blades simply didn't fit in the belt or holster, a requirement for a low TU last resort.
These days I'm simply playing it safe, without any blades. Covering fire, crouching, reaction fire, using two or four man groups, and lots of grenades.
I've found it safer to cover a doorway with a SMG or sniper while the grenadier lobs some explosives. Rather than send someone in and come face to face with a greeny and only 7 TUs left.