I can definitely relate to the speed issue having played an infuser many times against spike teams - lol.

Looking at the usage of Ether Prodigy though I wonder if speed is that much of an issue. Take a look at Idiot Savants and the El/Mo who used Ether Prodigy 63 times and Heal Party 148 times. Although casting quickly is a requirement the difficulty appears to be mitigated somewhat by using a party wide spell.