Probably the steepest learning curve i've ever seen, but if you put enough into it, you'll get a lot out of it.
Well if you're wondering about Victoria, I can certainly tell you that it's just as complex as the other titles. In fact it's more complex. It's actually so complex at times that I honestly believe that this game may be more complicated than it is to actually run a real country.
But the real question for Victoria is, once you've put the time and effort into climbing such a steep learning curve, is there a worthy experience waiting for you? Why yes there is. If you know what you're doing, this can be one of the most engaging, immersive, and downright addicting games available. You can really get sucked into the world of managing your national budget, maintaining your military, and watching the political spectrum of your country change over time.
Graphics really aren't a matter of much concern in this game. They do what they need to, and most of your campaigns will be played out in a big old map of the world, with sprite guys representing your military units.
Overall, there's not much else I can tell you about Victoria. If you put the time and effort into it (I still haven't figured everything out) You will be rewarded in the end with a fulfilling experience.