Many people probably already know about this, but for ranged classes that want to make the most of their followers, make sure to equip them with a Cold damage weapon, which allows them to snare mobs on hit. If you're using the Templar, get him a Cold damage dagger for the increased attack speed, so he can reapply the snare over and over again. For Scoundrel, give him the skill that allows him to fire three shots at once for an AOE snare. I've noticed the Templar becoming noticeably more useful as a follower for my DH after I equipped him with a Cold damage dagger, even though he had to sacrifice some DPS for it (but let's face it, he hits like a little girl anyway so his DPS doesn't really matter).
Does this mean that you should also use a Cold damage weapon? Maybe, but I've tried one out on my DH and found it to be of limited utility. The snare doesn't last for that long, and most monsters usually recoil when hit. By the time they recover from the recoil, the snare would've worn off. However, follower attacks don't make mobs recoil, which makes Cold an extremely valuable property for a follower weapon. For solo players, and especially Hardcore players, you need every edge you can get, and this will give you one.
Happy hunting, guys!