I was going to say something positive about random elements in gamebooks, but I think I'll do all the negatives first.
Dice usually have numbers on them. Even if the dice have symbols, you can express them in terms of a probability, which is a number. This seems a bit of an obvious statement. However, this leads to all the possibilities of working with numbers and probabilities.
If you use numbers, then you can manipulate numbers. This leads to a lot of work.
I remember reading a few choose your own adventure books. I think the only time I had to keep track of something was whether I had picked up some item. The other times, all I had to do was make a choice and enjoy the story. I didn't like it at the time, though. I wanted stats, so that I could get lots of items that increase them. I used to play Fighting Fantasy books with the challenge of finishing with the most items and gold pieces. More about that in another post though.
Choose your own adventure books were not hard work. Make a choice, read a it of story. Make another choice etc. This , coupled with a very non linear format where there were sometimes several happy ends meant that you could immerse yourself in the fantasy world without having to swim to the surface of reality to check an adventure sheet to see if some stat was good enough for you to do anything. Nowhere was blocked off to you because of some dice roll at the begining.
Of course, I could never improve anything. The only reward I had was a happy ending. But it wasn't complicated.
On the other end of the scale were certain Fighting Fantasy books which were laden with items which improved your chances in some way, usually in combat. This was great as it meant progression, but it also meant that some combats involved rolling several dice and it was difficult to keep up. right, so I have a sword that adds 2 to my attack strength, but I can fire an arrow at my opponent first and test my skill to cause 2 stamina points of damage, then deduct an arrow from my adventure sheet. Then every time my opponent hits me, there is a table to see how much damage it causes, so I roll a die for that, but then I roll a die because I'm wearing armour and it will reduce my opponent's damage by 1 if I roll a certain number.
Then I'd forget how to adjust my stamina because the attack strength roll was about 5 minutes ago.
The Sorcery! series was the worst offender for this, especially since you would be walking around laden down with four books worth of stat changing equipment as well as a huge list of spell components which you had to check every time you were given the option of casting a spell.
I loved the Sorcery! series for many reasons, but simplicity was not one of them. Rolling dice, then adding and subtracting modifiers can detract from the setting, themes and characterisation of the book part of the gamebook. It just turns into a number crunching exercise where I wouldn't care if I owned some wonderful piece of magical treasure; all that mattered was the numbers associated with it.
Fortunately, the items with modifiers did not spoil the feeling of Sorcery! and all of its diverse and interesting wierdness.
Legend of Zagor, however, did not escape so easily.
My feeling about the gambook is best summed up in this thread from the official Fighting Fantasy website:
"Go into a room, fight something, pick up item, leave room. Go into another room, fight something, pick up item, leave room. Go into another room, fight something, pick up item, leave room. Go into another room, fight something, pick up item, leave room. Go into another room, fight something, pick up item, leave room. Go into another room, fight something, pick up item, leave room.
Some books you cheat with because otherwise they are impossible. This one you cheat with just to get it over."
If a gamebook does need stats, then there needs to be a limit of the number of things (items, spells etc.) that can modify them and by how much. For example, maybe everything that restores stamina in a Fighting Fantasy book should restore a certain number of stamina most of the time to avoid confusion. Talisman of Death was good at this. The vast majority of things restored 4 stamina points with a few things restoring 2 and a couple of things 6.
If you go further and use dice to determine something, then ways of manipulating the dice roll should be limited. For example, all magical weapons add 1 to your attack strength and that's it.
Otherwise you end up bookkeeping, which is something I don't want to do in my leisure time.