[AZKen]

If you "back it up" with a plate with a hole in it, you can keep tapping harder and harder after penetrating oil. Once you get any tiny movement, it will go. The danger of cutting both sides off is you have created a burr to drive thru. That's bad. Try to determine if there is a burr and smooth it out. Also if it is held by a burr, you then "swell the pin" by hammering and make it worse.

Bottom line: If I'm not mistaken, you will be drilling new holes in everything so drilling it out is not a big deal. Bending the shaft by pounding is a big bad deal.
This pin will be hardened, so drilling it out will be no picnic. Maybe heat the shaft, (not too hot!) if that does not damage something else. That may open the hole.