I don't think the change was needed, nor the lack of synergy with Adrenaline.
You need to devote your deck to life to use adrenaline; you need a card space for the spell and then you need the quanta to play it. You will most likely have better targets for Adrenaline, like a crawler or a frog. It would be useful only to reach max water quanta fairly quick.. but what do you do with it? You can't bolt to death since the introduction of the quanta cap, so it should not be overpowered.
One interesting strategy is mixing adrenacrawler and adrenasponge. Coupled with ice bolts, it could be an interesting rush (crawler softens you up then ice bolt for the kill) - however, I am quite sure it would not be overpoweringly fast.
And why keep the unupped sponge at 0 cost? With a cost of 1
you need to have water production already to play it. In a duo, for example, this means either your mark or a few pillars/pends needs to be devoted to water. Without a cost, you could have a lot more freedom when building decks with Sponge, like having it as the only water production in your deck.
Most likely missed something I wanted to say.