There is a reserve feat (for example) based on acid. Essentially, it allows a caster who still has an uncast acid spell of X level to throw Xd6 (I think) at will without giving up the spell in question.
So, say I am a 3rd level character and have Melf's Acid Arrow memorize or I am a sorcerer with Melf's Acid Arrow known and a 2nd level spell slot still uncast. My caster can toss 2d6 acid orbs till the cows come home every level until Melf's Acid Arrow is cast (in the case of a wizard) or until all the 2nd level spell slots have been used for the day (in the case of a sorcerer).
Nice feats, huh? I think they give too much power to an already powerful class. Keep in mind, I only got a look at them today - I don't have the book yet in front of me.
I'm not so much worried about the power vs. Warlock aspect as I am in the additional power of the spellcaster increasing, though.