I will disagree a bit with my experience, specifically on the "Solo Disparity." Our DoTs are quite good and theyre comparable to the current Necromancer DoT suite at the same levels in terms of damage per minute. The lack of snare does hurt the shaman but you can root rot if you're in a space that you can't kite although it is difficult. I find soloing around DoT kiting things to be comfortable, and I would dislike a melee route for this class, I think especially with the new Cleric if you'd like to be a melee support that's your route. I enjoy the disease and magic DoT lines we have, I enjoy the fantasy of it. I will agree though that roots break far too often and theyre annoying, I think root breaks are way overtuned.
That's my two cents on the DoT's though and DoTs should really never be in consideration when it comes to group play, and this comes up in Necro forums too. You can't balance a DoT around a 6-man group killing each mob in 10-20 seconds, it's just not possible, they'd need to be transformed into something like rain nukes for them to be effective in group play. DoTs and group play in this game just don't go hand to hand, the ttk is too fast for both mobs and players. So I find the DoTs to be really good soloing personally and then when in a group just focus on healing and buff/debuffing.
