The espionage and item trade are pretty minor, you can scout places/stay hidden and observe troop movements, but it's very limited.
You can also seduce/assasinate commanders, sow dissent, undermine enemy dominions or launch raids and stealth attacks.
Some nations has also special units, like the R'lyeh which have a steal unit which will drive everyone in the province insane.
It doesn't have any elements that traditionally make up a grand strat. game like trading, diplomacy, alliances, taxes/allegiance and the like.
They have some of those elements, but not all that deep.
Game isn't really build for diplomacy story wise, since you each player is aspiring to godhood with no rivals allowed.
It still plays a major role in multiplayer games and is supposed to be pretty deep political intrigue, with a lot of secret pacts, backstabbing and lots of roleplaying potential.
Although none of those are actually ingame, true.
While I'd certainly say it's a very deep fantasy TBS, it's pretty standard other than that (troops tiers, RPG like commanders, global and battle spells and so on).
The units aren't really tiered, you can build everything right off the bat, allowing different strategies. And you'll be building cheap and expensive units both throughout the whole game.
Commanders are a bit more flexible, but I guess. You also have little choice on his development and the RPG elements aren't that importan, except if you get lucky with a good Champion trait.
Spells are somewhat comparable to Master of Magic, although there's a whole lot more of them and many of them have awesome effects and there's a whole lot more of them.
I'm not bashing it - I think it's a pretty good game, but I don't want people to buy it thinking it's going to be different to how it is, as I was kinda disappointed when I got it after hearing it talked up so much. It's a great game, and I'm sure with multiplayer/PBEM it'd be fantastic, but as a solo TBS it's just a fantasy TBS with a slightly different slant, tons of depth, but with a terrible UI and a massive manual in my opinion.
Never claimed otherwise, I merely jumped on the genere discussion.