(although i cannot imagine people using this on their own creatures practically speaking)
So you can't see people using this in the same fashion as adrena-staves, since if this card were introduced it would literally replace adrena-staves? Especially in unupped play, this would make mono-life pretty scary unless you had a fire or thorn shield, or were getting SoR'd scarabs up fast.
Current: Adrenaline

x4 + Staff

x2 + Flying Weapon

Flying Weapon - Off element and useless without a Staff.
Staff - Cannot play more than one or receive adrenaline without Flying Weapon.
New: Adrenaline

x4 + Frog

x2 + Regeneration

x3
Regeneration: On element, wider utility, but costs a bit more.
Frog: Can be played in multiples and receive adrenaline without an enabling card (flying weapon), does 50% more damage than Staff.
That said, I endorse this card whole heartedly, although exact balance might need to be worked out.