That's where the Ring of Unshackling comes in handy, my hard rocking amigo. It's duration also get's prolonged by Spelltongue - but every time it does that it also supresses new afflictions. It's like a re-appliance after every hit. No annoying afflictions (that can be supressed) at all. At least this was the case before the latest patch. Don't think they changed that - too specific. You can still be stunned of course. Like when they stun you and you can't hit anymore - I think then you also can't remove the stun affliction. For that situation I prefer the following setup: the shield you get from the drake in the Endless Paths lvl 5 (forgot the name, Brysomthing's Solace) + any other preservation item (like Blaidh Golan). Those stack! If you get stunned, switch to that shield setup (switching still works) and you will have +100 to all defenses. Same with prone. On top of that you can wear another item that has Break Out (-50% stun and prone duration). You will get stunned, but not for long and you will niot get hurt a lot with +100 to all defenses.
This doesn't work with paralyzed and petrified. Against Lagufaeth (who paralyze, not stun - sadly) you can use that shield Alia Braccia that you get from the monks in Twin Elms. It turns 100% ranged Grazes to misses and reflects them back. You just need to make sure that your deflection is high enough to let them graze. Use a Scroll of Defense and Stalwart Defiance, then it should work. Then they are paralyzing themselves all the time and it's a cakewalk. And then tehere's allways scrolls against affliction that grant immunity and... also get prolonged by Spelltongue!
@Raven: yes, seems bad at first. But on the other had it also crits now - which is quite aweseome if you have some means of debuffing deflection without paralyzing (like Binding Rope, Aspirant's Mark and so on) and buffing ACC. I would say it's even better in a party - if you're not using dumped PER and don't fight against monsters that are too high of level. For soloing this is bad, I agree. The good thing with the barb is that he can possibly stack 5/4 retaliations (that cause damage) a once (5 if he's a fire godlike): Battle Forged + Potion of Flame Shield or Mantle of the Wreathing Flame + Garodh's Chorus or Coat of Ill Payment or Hiro's Mantle or Vengiatta Rugia + Sura's Supper Plate. With high MIG, Greater Frenzy, One Stands Alone and Vulnerable Attack you can accumulate a pretty high retaliation damage. And then think of all the new items that do something when you receive hits/crits, like Binding Rope, that Laveder thingy, Swaddling Sheet and so on. I think it could be viable in solo mode - combined with carnage and the buff-prolonging setup that keeps up Savage Defiance and Frenzy and all other buffs all the time... But I never did a solo run, so who knows for certain? Also - to get to Spelltongue you will have to do beat a good amount of the game without that effect.
Maybe I misinterpreted your post but it sounded like you said it's good vs weak enemies.
That might be the case but against them you don't need it in the first place.