I think I should probably put a little more math in this topic, since with the reversal we're getting into the land of averages...
Let's say you have three Elite Cockatrices on the field, since this is a Life card unupped... I'll leave off the upped version for now, since showing the unupped to be too powerful is sufficient. Your opponent is running a balanced Gravity deck, which I picked since killing a creature would be irreversible (what if he played a new creature in the same slot).
Before playing Help Me So:
You have 5|5, 5|5, 5|5, he has 8|30, 8|30, 8|30 (three Massive Dragons). This is a total of 15 attack for you and 24 attack for him, the HP is irrelevant for now, since the dragons will not die in your suggested five turns (-10 HP).
Each turn there is a shift of +3 attack for you, -3 attack for him, and the cumulative damage added/reduced is as follows:
Turn 1 = +3 / -3
Turn 2 = +9 / -9 (that is 3+6)
Turn 3 = +18 / -18 (that is 3+6+9)
Turn 4 = +30 / -30 (that is 3+6+9+12)
Turn 5 = +45 / -45 (that is 3+6+9+12+15)
Every five turns, friendly creatures will have an average of (3+15)/2 = +9 attack boost, while enemy creatures will have an average of -9. The turns they spend at extremes of this spectrum make up for each other.
For the price of one permanent and 5
, you will deal 45 more damage than you would have otherwise, while your opponent will have damaged you for 45 less than if you had not played the card. This is mono-element and over twice as strong as Unstable Gas, though its effects happen over several turns; one might argue that Dimensional Shield can block a full army of much greater than 45 attack power, but Dimensional Shield...
1. requires a duo deck to create synergy with Empathic Bond,
2. is vulnerable to Momentum,
3. does not increase your creatures' stats, and
4. may be stolen for a turn or two of the same effect, rather than somewhat mitigating the effects already suffered, as this card does.
If you ask me (which I'm honored that you seem to be, and I don't mean to criticize destructively, but constructively), this card is trying to do too much at once. Here's a suggestion: make both cards Life, lower their cost a little, and have them affect only friendly creatures' HP and enemy creatures' attack - a haven, if you will, not an offensive card but a defensive one. The effects would still need to be reversed in short order (somewhere from 2-4 turns, I think, my instinct is telling me 3 is nice and round), because reducing an army's attack permanently is a bit too strong. 0|+1 friendly and -1|0 enemy is probably best for both versions, the upped just would have a lower cost.
This change will fit Life's theme very well: it likes fragile creatures, so protecting them a little is a nice temporary buff, and reducing enemies' attack sounds a lot like you're trapping them in roots or something.
