Yeah, that all be true. 20hp on a bench under no load is a whole different kettle of fish from an older 10hp Kohler, Briggs or Tecumseh. These newer engines are pretty much fluff. I have a 20hp Twin B&S on my JD L111 and I can tell you that the JD although stronger than many of the other new ones cannot shine a candle to my Cub, not even to my old Craftsman and it wasn't all that strong. I am curious to see what the difference will be when the 12hp 129 hydro gets up and running.
When people talk HP today it is like talking lemons, apples, grapefruits and kiwis all in the same sentence. There really is no common ground. That is why to me the drawbar rating would be the most accurate - but it is little understood by the average person. Even though I have been involved with engines of different types all my life, hp ratings for them all varied immensely.
Yes, you do have a valid point. Many of the wings today are made out of 16 gauge or thinner stock which will not hold up well. The kind of tins used on say an IH-50 or a 30 year old Ariens, Toro or even a Craftsman were much thicker - 14 and possibly 12 gauge or thicker. That stuff will hold up to cutting through banks. One would hope that if someone is making a project like this that they will use the thickest stuff that they can and it makes sense.
Heavy wet snow is going to be a bear no matter what you do. Sometimes a blower simply is not the tool to use - I have my 13hp/33" cut Yardman -- it is a 2000 I think and it packs some oomph, but it will not blow slush or heavy wet snow. When that happens I simply call Ray with the loader on the Massey. Lot easier on me and the equipment.