I don't think Nidhogg's mechanics are all that difficult to understand and execute. If anything it's a somewhat harsh DPS check! I say somewhat harsh because it's not really that bad if people are trying to hit their buttons sorta correctly. Weeping City is a bit more mechanic heavy than Void Ark but I'm sure it wont be long before most people have learned what they need to do.
If they nerf anything it'll probably be the DPS required to kill the adds on Nidhogg or they might just wait til it nerfs itself due to gear.