Brad- I was just thinking after reading your other post on making swords, how about random tech tree/ random starting weapons.
You don't know what your first group of warriors weapons are going to be like until you settle your first city. Once you do you find out what your basic starting weapons are, say I get daggers this game and the next spears (you could run the chance of starting with say +1 dagger or a short sword). Other possibilities are you could start out with training (though you won't get a better starting weapon).
In all the games you get access to all weapons axes, swords, spears, etc... though you might not get to access the best ones down the tree. You could explore the world to unlock them, or kill off your enemies to get them or tough luck you don't get them in certain games. You can't always rely on your favorite weapons.
The same would go for spell books, certain books contain x spells, some games you get the whole book, others well you might be missing a spell or 2. Same as above for completing the book, explore, fight or some games they are gone.
And yes you guess it for techs too...