I love the Fighting Fantasy games because they were the ones that started the gamebook and brought it to the popularity it has; however, like most, I always disliked the fact that you could possibly get instantly killed by a boulder trap because you went right instead of left in the cave
Great intro monologue! I'm wondering what your playtesting method is. I have a background in quality assurance for computer games and I apply those methods to my playtesting groups. It doesn't always work out.
For me personally, I literally play through the entire book as a 'gamer/reader' so for each DestinyQuest book that would probably be about 9 heroes on average, but sometimes more if I feel I need to double-check. I just put all the combats into a document and play it through that way. I don't rely on software or any algorithm because with something as complex as DQ with heroes having 16 + abilities in some cases, there is no program that can tell you 'this fight is balanced'. You need to play it and experience it, with the abilities that would be available for that hero. As for working with 'playtesters' I actually have limited experience, because DQ is so long and complicated I tend to do much of it myself - but with my last book I did open up to outside testing. We actually ended up with a colour coding system of easy, medium, hard for each combat - and just tracking experience and other stuff. That helped me tweak a lot of stuff.