I read some interesting analyses, but I think you guys are forgetting some very important things: RT acts as a +1 draw to you. It functions as a procrastination via creature control. Now, Tsunami's EQ costs 3|2. EQ (the card) costs 3|2. Gravity Nymph's ability costs 3|3. Black Hole costs 4|3. Purple Nymph's ability costs 4|4. Antimatter costs 7|6. Pulverizer's ability costs 3|2. Steal costs 4|3 and explosion costs 3|2 (Explosion is the analog to destroy). Blue Nymph's ability costs 3|3. Unstable Gas costs 6|5. Gray NYmph's ability costs 1|1. Aflatoxin costs 6|5. Life Nymph's ability costs iirc, 2|2? Adrenaline is 4|3. We can ignore the nymphs if you want - this is all to draw one thing to your attention: A pattern. The card itself always, always, ALWAYS, costs AT LEAST the amount of the card's analog activated ability.
Rewind costs 2|1. Eternity is 3|3. What's the odd ball in this game? Eternity is not going down in cost, so I motion to you that rewind should cost, at least 4|3! In the interest of fairness for the game, Eternity's cost was driven to 3|3 for its powerful effect. Name one other card in the game where the card's activated ability cost more than the card itself (i'll grant light nymph, but face it, luciferin is a low tier ability, versus high tiered ability). The entire point of the activated ability is that you can play the card continuously. Why? The card with the ability can be destroyed; the card itself you activate directly from your hand as a spell and cannot be countered by offence (only by defence). think about it a little bit. Rewind has a powerful mechanic, but I'm arguing from the mechanics of the game here. Justify what makes Rewind so special (we know it's powerful) that it gets to deny the game's balancing mechanic?
Rewind's mechanic won't change - nor will the game's. Assimilate rewind to the game's mechanic. Rewind should cost 4|3, and that will break its abuse.
Good try at a balance model. It is one that seems intuitive at the first glance. However it seems to break down when looking at weapons.
I think you missed the difference between the casting costs and the attacks not to mention the difference between mono and duo activation costs.
Earthquake: 3|2 + 1 card casting cost
Trident: 3|3 + weapon + 1 card casting cost + 3|2 activation cost (duo) -> 4 attack + Earthquake ability
Reverse Time: 2|1 + 1 card casting cost
Eternity: 6|5 + weapon + 1card casting cost + 3|3 activation cost (mono) -> 4 attack + Reverse Time ability
Deflagration: 3|2 + 1card casting cost
Pulverizer: 4|4 + weapon + 1 card casting cost + 3|2 activation cost (duo) -> 5 attack + Deflagration ability
Note that the activation cost is always greater in these direct weapon comparisons.
Activation Costs
Earthquake: 3|2 duo > 3|2 mono
Reverse Time: 3|3* mono > 2|1 mono
Deflagration: 3|2 duo > 3|2 mono
*Eternity could have had a -1activation cost upgrade rather than the atypical -1 casting cost upgrade
As for the +1 card:
It either functions as "+1 net card and destroy x quanta" (if the creature is worth replaying) or as kill target creature (if the creature is not worth replaying)
PS: White Nymph can be explained by the difference in value between healing and regeneration.