I think you misunderstood me... the first play-trough should definitely be done without use of any guide. You will inevitably not get the best result possible for some events, but it will give you a great experience. Even if you might mess things up completely.Not using a guide personilizes the experience a bit.
Like playing 'SaGa' games without a guide.
I could either follow one in order to get every single sidequest done, making it the "Perfect Run", or I could do stuff on my own and have in the end a more personilized experience.
And if I'm happy with the game, it's kinda exciting to play it again, just to see new stuff I haven't seen in my first run... which wouldn't be possible if I would have done absolutely everything before.
Second (or third, if you made a complete mess out of first) playtrough on the other hand is another matter, that should be done with a guide to see what you miss.