Why don't you let the prot warrior pick up the adds? Between charge/intervene/heroic leap it's pretty simple to get the adds if they spawn on opposite sides, also with Vigilance on you he'll have unlimited taunts.
For Maloriak adds use nameplates and when they spawn throw your shield at the ones that spawn next to eachother and use judgement on the other one. I run with less then 1% hit and usually only miss one every once in a while, if that happens I just either taunt it with Hand of Reckoning since that doesn't miss or I just wait and pick it up with Judgement when it's off cooldown. The adds don't do much damage so a healer can survive a little with it beating him.
What I used to do when I was responsible for add duty was have our Holy Paladin use Righteous Fury to kind of funnel the adds towards them in case I ended up missing, then I'd just use Righteous Defense to get them all. Now that we are killing Heroic Maloriak I usually tank him instead of adds and keep a set of gear specifically for fights that I need to interrupt something since we roll with only 1 reliable interrupt in our raid. I use the Right Eye of Rahj in my hit set currently but I'm hoping to pick up another BH Mastery trinket and reforging some Hit on it for the on-use.
Here is an even wackier idea...why not do what tanks have been doing since vanilla and have a couple of sets of gear for different things? Remember resist gear sets? Remember some tanks having max stam kits, and avoidance kits?
It's not hard to pop on a different set of gear you have reforged and gemmed differently for different situations at all.
I've been running with 7% Hit on my Tankadin, but I've been thinking about dropping down closer to 5% in order to stack more Mastery. 5% is enough to be hit-capped in order to pick up/interrupt any non-boss Mob, and if you're on a Boss, Vengeance typically takes care of all your threat needs.
Also, the problems with "lol noob just taunt them lol" is that A) our taunts (esp. Hand of Reckoning) no longer deal ANY damage and B) taunts wear off if you don't generate additional threat in some way. Hell, I've even had adds that I Judged snap back off of me and run after a healer who was bombing someone in an Ice Block or had the Fire debuff or whatever.