Tried soloing him today, it's kind of a breeze with MR gear, his rooting attack that used to kill now does like half health so that's cool. But, he still has a ton of health, I don't think it scales for player count, I ended up running out of time in the fourth area. Didn't lose time to carts, just to having to kill the jagras. Seems doable with my unoptimized build.