https://www.youtube.com/watch?v=d0VMF4WOcrc
Have only tried soloing Hydra so far, but it was a lot of fun. Makes you actually pay attention to all the mechanics, except for Radiant Breath. Surprisingly, not as easy of a fight as you'd think, especially with the frequent tank busters and dealing with the Wyvern every time it pops (if you leave it up too long it'll cast a damage up buff on Hydra).
Luckily Hydra seems to have a high miss rate, coupling that with Featherfoot really helps. There's a few things I didn't do that would've helped more, like baiting out the tail swipe every time I got the chance. Unfortunately there are also areas where I really couldn't do much about due to needing to hold onto Vengeance and Raw Intuition for adds - RI could be used a bit more liberally but was risky if an add phase was coming up soon. Got hit by 2 of the AOEs as well, but luckily got a dodge roll on both.
Infirmity isn't that big of a deal, but White Breath is typically followed by a Triumvirate so things can get extremely difficult very quickly. Another giant problem is if you step into one of the ice circles as that will give you a heavy debuff and make the very quick AOEs even harder to dodge. Fire circle isn't as bad since it's a fairly low potency dot, if you have to move into one then fire is definitely the way to go.
Other than that it was a pretty exciting fight. Couldn't really go into Deliverance due to needing the self healing/mitigation from IB very often, but I imagine for DRK or PLD there might be more opportunities. DRK, I feel, would actually be really good for soloing this fight due to the flat 20% mitigation and constant self healing from Souleater. WAR was a lot of fun though, always had to think on my feet with every phase. I'd definitely recommend giving it a try if you haven't already.
Anyone else try soloing bosses? Or dungeons?