I've got a conc barb too, and here's my two cents:
- Your dex is high but I personally wouldn't restart your char because of it. Just put the rest of your points into Vit. With your high dex, you should be able to get max blocking with almost any nice shield you find.
- My weapons were kind of slow too. The "Honor" rune word is pretty nice and easy to make; find a nice exceptional or elite sword and try it out. It's not huge damage but it might help. Also identify all rare swords! If you find one with lots of enhanced or elemental damage, you can use the cube to upgrade it. This is what I'm currently using and it works great!
- The merc: someone here said you should go with a defiance merc. I have to disagree! Your conc barb should have tons of defense already. I'd reccomend going with a might merc (Nightmere Act II offense merc). That will help your damage a bit. And with your huge buffs, he should be able to survive pretty well (mine almost never dies!). Just give him some life leech and he's good.
- Dying to little guys: Hell in 1.10 isn't like the other difficulties. If you get surrounded -- RUN! Just use howl a couple times and then run away. Have no shame!

A few will follow and you can kill them just a couple at a time. Use taunt to get them if they don't follow you.
- Switching spells: One thing you DEFINITELY want to do if you haven't already is change the mapping of your keyboard. I can't imagine having to actually use the F1 or F5 keys to switch skills! Move them to buttons that are easy to find, like 'a', 's', 'd', 'f', 'v', etc. I think this is in Options->Controls or something. You only have to do it once and it sticks for all chars.