Playing poison druid right now, mana issues are overwhelming. Roots and harvesters cost way too much mana at least for early game (lvl 106 so far). Yes, i use mana sweep RW on switch and mana regen MOs on jewelry and 1-2 rows of mana pots, had to add them to loot filter.
Also roots cannot be casted on non "land" surface, so you cannot target mobs that are flying over rivers and such (Ioss, arcane sanctuary etc etc).