In all honesty, if I was worried about it, I would just replace the door with one more suitable (and probably the frame), as well as replace or re-key all the locks in the place.

That takes care of the door and it takes care of any former owners or neighbors still having a key to your place.

Another option would be to replace the glass with something resistant to breaking/shattering (i.e. polycarbonate/lexan). The only thing to keep in mind with it, is that it scratches much easier than glass and it breaks down over time when exposed to UV light. Therefore, you'll probably end up replacing it every few years. I'd still have the locks re-keyed/replaced though, for the same reason mentioned above.