Trade for a ski boat. I'm actually not kidding. My brother has a 19' Mariah and we spend a week at my parents' lake house every summer and I really miss my Supra when we do. There really is nothing you can do about the wake because the wake is a function of the hull and the outdrive. There are small things that may help a little like moving people forward, and of course skiing faster to get more hull out of the water (that may only exacerbate the face plant issue).
Even though it is not the best pull, you should still be able to ski well behind it. If you are jumping and face planting you are probably not hitting the wake on edge. You need to slice through the wake with speed and stop pulling when you get to the second wake. The dynamics of skiing behind an I/O are different, but the skiing fundamentals are the same. Work on your technique and the boat will suffice. But if you want to get a lot better or ski in a course, you will be much happier with an inboard.