The nemesis gets tougher and tougher after each kill, so if he is killed immediately after he is spawned, he isn't going to be that tough.
That has been my experience with it as of late, piece of cake, my character is much stronger and after a few tips I got from reading people here and progressing, I just got better at the game, I played so so not much time ago.
Yes it can be a bit dangerous when you spawn them and quickly swap back. On really tough difficulty or grifts and bad combo of affixes, it can be deadly. Of course it's a bit easier on PC with mouse movement, wouldn't try to do that on a controller.
Bracer depends on the class and build of course. On my "main" Barbarian I use Reaper's Wraps as health globes are integral into my build and they replenish my Rage a lot.
http://us.battle.net/d3/en/profile/Malosar-1887/hero/45836478
On the console by pressing the nexus button you can swap items back with the game paused, I think, but it's not as fast as using a m+k combo, I don't mind fighting the mobs with the Nemesis bracers on anyways, but in Diablo 3 I am gold digger lately, it's not normal that Treasure Goblins opening up the portal to The Vault never did that again for me.
I got 12,000.000 gold in one run at The Vault.
Been studying your characters and I noticed that your Barb uses a Cindercoat. I got one but thought it was pretty crappy and there it is in my mules' stash. Don't you find yours a bit low on armour for a Barb?
I like how you chose the Depths Diggers for pants, I have those too. If I can live without the backflip from Evasive Fire -still doubtful-, I am warming up to the idea of changing my primary skill that regenerate a resource to something that does even more damage. That might need some testing with the DH. My top is 6,000.000+ damage.
You seem to like the Infernal Dye, I rarely use that dye thing, I think all it does is changing colours, but my female DH is pretty already.
Love that amulet -crazy critical chance-
and those boots. (the effects of your boots remind me of Baal leaving the prison where Marcus dies in Diablo 2, a trail of fire behind him, pretty cool)
Your DH still has a loooooooot to go. He isn't equipped with anything but rares, save a couple of spots --which means you got going on with whatever you found in your game. I have some low level legendaries I got from friends when they sent me gifts at the beginning, and some others waiting for my future DH -in the distant future-, but yes, I can see it's not as easy to equip a low level character as it was on Diablo 2.
I mean..., your DH will do fine because rares are so much better on Diablo 3, but it is surprising you haven't found a few set or legendary items on low levels to make things easier for him with other characters.
In my case, I've found some stuff for Wizards, Barbarians, etc, with my DH, but it has been quite scarce.