Fair point. I was iffy about four invocations anyway, so that can drop to 2 or 3.
I had not intended on counting the prerequisites any differently, since a fair few of them are fairly strong effects. I was also considering gating some of the current invocations more as well, for both this and the Warlock in my games. That is a different thread though.
On this subject, my main reason for skewing high on invocations is the recently increased number (though I will be cutting a few of those out entirely), and the talk I have seen about warlock getting few invocations. Which way would you lean, 2 or 3?
