FS15 was probably one of the biggest gaming surprises for me in a long long time, I mean who thought something that theoreticly should be mundane be so enjoyable and soothing, i came quite late to the party on 15. so its quite exciting to be there from the start for 17.
Purely on the back of 15 i preordered 17, even if it does end up being just an updated version of 15 with more features i'll be happy, I havnt played 15 purposely for almost a month now purely so i didnt wear myself out on it, i'm eagerly awaiting the release.
I was the same with FS11. I found a demo randomly, decided "hmm, this looks OK, if a bit cheap", played the base FS13 (no mods and it still looked a bit naff) then the model detail just skyrocketed with FS15 (though the graphics in general still looked a bit average) but now FS17 looks pretty damn good, and map makers could have a field day with the new lighting system*.
FS17 is pretty much FS15 made much better. While there's no single new "wow" feature being introduced, the level of polishing over FS15 is nuts. The silage pits, the new grass fields, the tip-anywhere feature (and the newly leaked conveyor belt that will accompany it) and so on and so on. They've taken the best mods and made them awesome.
* Think multiplayer on a detailed mod map around a village in the evening, with all the street lights and house lights. I used the word a few times in my post earlier, but it will feel so immersive...
Would you say this game is more about driving the vehicles (similar to Euro Truck Sim) or farm management, or both/either?
It would probably be more accurately described as "Tractor Simulator", as while there is livestock, the work you do with them is entirely done through driving machines. The management aspect is fairly limited... indeed it doesn't really exist.
The knowledge needed is pretty slim if you want it to be, but as Mike says, the new fertilisation system means it could be quite complex, but I fully expect you can enable/disable this system in the options, as it could get very tedious very quickly for the casual player.
You could play as simple as harvest > sell > buy > plant > harvest if you wanted to, upgrading to bigger machines with the money gained, though the game would quickly become boring if you just did that on your own. Multiplayer is surprisingly fun even just playing the basics, and that's where it can trump Euro/American truck sim, as everyone is usually around everyone else, helping each other.