First advice is to assure, that the game will work properly. So if you already downloaded the demo and it didnt work, you need technical support. Then there should be figured out if there`s an issue, and of course it must be resolved.
2nd you get all the game-features if you get the basic version. The more expensive versions are mainly to support the developer-team. So from your point of view it is absolutely enough to buy this, so your own risk is acceptable, if you wont really get in touch with this game either.
But different to other games, in histwar you can benefit from several layers of AI. The AI basically is in command of each and every unit of your army, and cares about what can be considered as proper decission from its perspective in the very instant of action. Histwar isnt really about micromanagement, although you have the opportunity to do so. Preferably you are to give the major directives to your commanders and only intervene if you feel further meassurements are necessairy.