Flyguy,
Good post, and good points all. Back in the day when a good Lycoming 360 could be had for a song, and the Avcon conversion kit was cheap, it may have made sense to convert one of these airplanes. Now??? Bring money, because you'll never recover the cost. If you don't care about that, fine. Just go in eyes wide open.
Now, as to the performance aspects: you are right on with most of your notes.
The difference with a big engine airplane is that I am airborne and climbing in less than 400 feet at max weight. My climb rate is high as well.
On skis or off airport, or most of all on floats, a stock engine 170 is a dog. Pure and simple. Those, however, are very specialized endeavors, and if you don't or don't plan on going there, the big engine is a boat anchor.
Just look at the takeoff run of a stock engine 170 on floats sometime, even one with a light load.
Not disagreeing with you, cause as I noted, your post is accurate.
It just depends on what you want to do with the airplane, and the name of this list is "Backcountry".
I went in and out of Smiley Creek last summer with my airplane, and it was warm. Piece of cake. I've been on glaciers at 7200 feet on skis. A stock airplane would still be there.
MTV