No, the disease isn't that dangerous, and a Druid can clear it with symbiosis. Your pally can clear it too if they're able to.
Every healing comp is probably going to have some weakness and some strength when it comes to dispels. Just plan for that accordingly. Unfortunately, rather than doing that, people play the overturned card instead as an excuse. Newly formed guilds and pugs have killed horridon on my above average pop server.