I still don't really get why people don't like Entangling Shot. The very first rune makes it a hugely viable killer, and one that stacks well with other passives and gear combos. Whilst it's not perfect as a single target spell, it is great for groups. And most of the time, you'll be facing groups.
4x75% damage is 300% damage. Those hits crit normally, they count as hits for life-on-hit, they can slow/freeze with cold damage (redundant) or take any normal elemental effects (specially on crits). Plus it's free. Actually, it gives you Rage.
What's not to like? You're doing a nice spread of damage that will always slow (those chains go for about half a screen if you keep firing), and can get all your passive effects on four targets by just hitting one. With the slow, you'll find that you have a leapfrogging effect, where the slow wears off one, they jump to the front, get chained, then the pack behind them runs forward and gets slowed in turn. Don't think of it as a 4 man slow, it's really a whole mob, on demand slow with decent damage. I'd have to test it, but I swear I've seen damage numbers from other skills on chained enemies as well sometimes.
You have your Cull the weak passive that makes it do 86.25% damage. Times that by four and it blows away hungering arrow for basic damage as well as being reasonable crowd control.
Try using a hand crossbow with some cold (or lightning) damage and a quiver. Take Entangling Shot w/ Chain Gang, Caltrops w/Bait the Trap, Vault w/ Rattling Roll, and Passives of Archery, Sharpshooter and Cull the Weak. It's a level 54 build, but you'll find that Entangling Shot holds its own pretty well. Drop caltrops, open fire (spread your fire a little), vault away, repeat. It works quite well in Inferno, as long as you have decent fire speed to maintain the slow and don't get too surrounded. Always Vault, hope, Vault again if you do (or use SS if you have it as well). You can also drop Cull the Weak if you want a different passive.
28% or more crit (without any gear at all), plenty of slots open for single damage, escapes (SS) or AoEs, enough slow to consider yourself a bit of a crowd controller. What's not to like?
Entangling shot doesn't do everything, it isn't the best at anything, but it does do everything well enough with just one slot that you could ever want when kiting or AoE'ing to have a place on the taskbar at all times.