I deal with rd by microing faster.
http://www.twitch.tv/microfastsc2/c/1791205 (mp10 extra health reflect dmg phase beasts.)
I love you:). So many people crying that beating RD has nothing to do with skill and here you are, posting a video showing RD being beaten with skill. Nice.
To the OP, my personal choice is Acid Cloud with 500+ LOH. Drop one to keep my health from falling too quickly while bear spamming and spam Acid Cloud if I need a heal, the coefficient is insane. I really like this setup in general just because it makes me extremely hard to kill, high mana regen with LOH and acid cloud means I can spam it if I get trapped in a corner or something.
Horrify with the armor rune is another good way, used that quite a bit too. Your damage to mitigation ratio is kind of high so your health will still drain, but not very fast. When I would run this it would be Horrify->bears->Jaunt (to heal)->play defensively until Horrify was back, repeat if needed.
Depending on the pack and if you continue to run Sever, one trick you can do is to pull more stuff. If it's only dangerous because of RD (i.e. Plagued, extra health, RD, Molten), then getting a few more white mobs in the middle will mitigate the damage, since your bears will hit them too. Killing them with Sever will probably heal you to full.
A HUGE thing you need to know about using Spirit Walk with RD is to know when to use it. You'll see a lot of Witch Doctors using it as soon as they cast bears. This is not what you want. You want to be in SW only when the bears are actually hitting the target and they're kinda slow. Get yourself an opening where you can spam, start it up and then right as they are hitting you use SW.