Desiccation unupped is a better version of the UP Thunderstorm. Both in the value returned for the cost invested but also in the utility and versatility of the usage. (1 Desiccation is useful. 1 Thunderstorm is rarely useful)
People should remember: When I say OP I might mean needs to cost 1 more or I might mean 2 turn Sundial. Upgraded Desiccation is no where near the 2 turn Sundial.
A comparison Tiko used was Cremation + Damsalfly + Firestorm vs Upgraded Desiccations.
On the fire side we have 3 cards, 3 upgrades and a gain of 3

+ 1 of each other
On the water side we have 1.5 cards, 1.5 upgrades and a gain of 1.5

(with the estimate of 5 creatures)
From this I would conclude that it is imbalanced but not UP. (aka OP)
What if it dealt 1 damage upgraded like I initially misread? Cremation + Damsalfly + Firestorm vs Upgraded Desiccations.
On the fire side we have 3 cards, 3 upgrades and a gain of 3

+ 1 of each other
On the water side we have 3 cards, 3 upgrades and a gain of 3

(with the estimate of 5 creatures)
From this I would conclude that it is less imbalanced but is now UP.
What if it dealt 1 damage upgraded like I initially misread but cost less to cast? Cremation + Damsalfly + Firestorm vs Upgraded Desiccations.
On the fire side we have 3 cards, 3 upgrades and a gain of 3

+ 1 of each other
On the water side we have 3 cards, 3 upgrades and a gain of 6

(with the estimate of 5 creatures)
This looks about balanced to me.