Druid is pretty solid, not the most powerful class, but is far better than the worst classes. I'd say its leaps and bounds better than Shadow Knight, Wizard and Magician. I think its better than Shaman, Ranger, Paladin as well. IMO its a mid-high tier class. I place it under Monk, Enchanter, Warrior, Necromancer.
33k DPS in a 40 chain. But for longer chains my DPS falls between 25-30k. But the DPS readout is underestimating Druid's killing speed, because most of Druid's DPS is AOE, and DPS readouts don't properly take that into consideration. The DPS varying a few K here and there is due to the randomness of tornado mostly.
Some things to note about Tornado's DPS:
Higher damage weapons don't necessarily boost the DPS of Tornado over a 1H + Orb/shield. The damage value on the weapon is irrelevant. Only its stats matter. Warlock's nemesis gives a higher DPS boost than a Singed Cudgel, and that's with 1h blunt skill maxed out & considering druid doesn't gain skill levels with piercing weapons.
+15% physical and +15% magic upgrades on the same weapon give the exact same damage boost. Although the later boosts the DPS of his other skills.
Intelligence raises Tornado & Earthquake damage.
If you upgrade weapons for Druid, upgrade magical damage.
If you're thinking Staff of Sentoth + warrior set on a Druid for crazy tornado damage, you'll be disappointed. The strongest gear setup is full set of Sorcerer's + 5 pieces of Warlocks + 2 pieces of Phantasmists + Archmage shoulders.