ph0rk
Friendship is Magic, and Magic is Heresy.
This is a good change, although it opens up a can of worms with multiclassing that, hopefully, they will address.... which is exactly why WotC is replacing "1 per SR" abilities with "PB per LR", so classes remain balanced across different play styles.
But the math for Warlock might not fit that rule, probably too powerful. IMO doubling their SR slot count should be about right.