There is a couple reasons this won't work. One the computer mechanics can add more variance within the attributes beyond a scale of 1-10, and it will do all the computations that we dont want to take the time to work out in the real world. I love this. a dwarfs attacks have to be delivered with more force than a goblins, yet he has a 3, just like a goblin for strength. Hopefully the comp takes it to the next level dwarf strength =39 while goblin equals 30. The next issue is balancing wont work the same as far as unit selection, I imagine you will be able to field broke as h3ll armies in the computer games, it will happen, and guess what the comp will have at least as broke an army, but it wont be just one, it will have 5 of them roaming. (not counting what they will have if they allow major chaos invasions)
Next the comp will not be able to be a kunning as your opponent, and eventually you and I will figure how to beat the comp easily with weaker and weaker armies. Maybe the last reason is the scale of the unit sizes. most inf blocks in Fantasy are 20ish, but might range up to 40 or beyond, I am looking at you Zombies, Skeletons, Slaves, Goblins, Marauders, while in Warhammer Total War the units will likely range in the 100s. Yes they will let you scale the size within the game, but i wont do this. If I have the comp to run it my units will be as big as I can make them.
So to wrap up. 1. to see your army scaled in size. 2. to see your army scaled and very beautiful. 3. to see the brokeset army the game will let you come up with. 4. hopefully some built in balancing on performance and attributes to make the fighting more 'realistic or loreistic'. 5. Maybe just maybe you can get the good guys to win one.