That's so cool! Especially when you have one of those cover illustrations where it's looking right AT you, it seems to beg for some interaction via a word balloon. It seems to be considered gauche and declasse to put dialogue on covers these days, like HEY, DIS IS SOME FINE AHRT HERE, show some respect!!!
I'm not saying we should turn back the clock to taping plastic 'free gift's to the covers or anything (the horror! the horror!!), but hey they should lighten up a little... It's supposed to be fun!