Steam will soften the quill, but I've never had it do anything to the glue. The feather will come off easier, but the base of the quill will stay stuck to the glue and the glue will stay stuck to the shaft. So, I wouldn't recommend it.
I'd take a small exacto knife and carefully run it between the feather and the shaft several times on each side, going just a fuzz deeper each pass, until you make it through the glue. It'll work if you're patient and have the time to kill.
I usually have a few arrows with messed up fletching anyway, so those are the ones I strip down to bare shaft with. Run the blade WITH the shaft's grain. If you go against the grain, you risk digging into the shaft. You stand a very good chance of messing up the crown dip in any case.
If I don't have any bad fletches and I'm desperate to bare shaft, then I figure the price of new feathers is less than that of my time and impatience.