Is this too similar to Silence?
Would it be improved if it were even less similar to Silence?
I really don't think it's too similar to Silence. The one similarity that they share is that they stop spells from being played (which I will admit is a big part of what Silence does). Silence is also used to force discarding, serve as soft PC (Dim Shield, Wings)...in my opinion it seems like a weapon to go hand in hand with Fractal more than anything else. Adenosine on the other hand seems like it would go hand in hand with Mitosis since Mitosis is slower to generate creatures and would thus need more turns of protection. Whereas Fractal is typically an instant burst of damage and requires a single turn of protection for it to be catastrophic. I also like the utility of the healing function, to be honest.
I don't see much of an alternative to the card compared to its current form. I suppose it -might- be possible to change it to where only creatures are unaffected by spells instead, but that doesn't fit the name of the card at all in my opinion.
I figured I might receive some opposition to the idea of this card being similar to Silence, but with cards like Anubis and Turquoise Nymph being completely redundant as well as Quint and Cloak providing a somewhat similar scenario I rationalized that it wouldn't be out of the question.
As for the healing, I feel it's absolutely necessary. Given that you have cards like Adrenaline and Mitosis in the same Element, a 2 turn negation of spells would not only mean that the creature targeted could not be destroyed by spells, but also that the opponent could not save themselves using their own spells. This is part of the reason why outright immunity to CC for Life's creatures would be so strong - it has such incredible damage potential. I'm not so much concerned about Life being given more healing given that even with 1 more source it still wouldn't possess the highest amounts of healing among the 12 Elements - Light and Darkness would still possess more forms of healing even if this card were implemented.