Structural issues? Well, of course there are issues; the critical thing is evaluating them, and that is likely beyond most amateur NAs.
Second issue is keeping the water
out. Hunters being fairly lightly built vessels in general, the hull likely flexes a bit whilst sailing and keeping a good seal between hull and glazing isn't going to be easy. Cutting a big hole in the structure isn't gonna help with the flexing, either. How much of a problem will this be? Hard to say,but the consequences of getting it wrong are not so nice to consider.
I would not do this myself... risking really buggering the boat in order to gain a small bit of visibility is a poor bet IMO.