Imperator: Rome is probably my favourite Paradox game.

Honestly, after Marius, it's seriously good. Even playing as a tribal nation which others seem to be saying is samey (it isn't, really, and there's a lot of unique nations to form).

The characters aren't as great as CK obviously, but it's not a character-centric game (though they are important and a good chunk of the game - to be honest, some of these have been as memorable as some of my favourite CK2 characters).

The internal national politics are probably the best of any of the games. The population is a bit more simple than Victoria, but religion plays an actual role so it's just on a different focus. It's also the only Paradox game to actually model the fall of empires, which is nice. Still blobs, but less, and it's more difficult to keep it together unless you know what you're doing (or forming Gaul lmao).

The international politics are great. Interactions with other nations is great. But the key focus is trade. Trade is better in Imperator than any other Paradox game except Victoria II, though that's a bit of an unfair comparison since the entirety of Victoria is economics.

Conquest with the Marius update is excellent. A wonderful model of the period, with levies growing naturally and legions being extremely powerful if used correctly, but not gods. The mercenaries are really ♥♥♥♥♥♥♥ cool, since you actually see them on the map, and hire actual groups that follow orders, but still act as independent groups and can be bribed (which seems OP, but is expensive, though really useful when playing tall - needs to be in EU5 if that comes out). Your own armies going rogue can be annoying, but again it's just another example of the systems being masterfully intertwined. Really, they all work together well, unlike some of the DLC-retrieved mechanics many other Paradox 4xGS games suffer when they're just piled on.

Really, I highly recommend Imperator for anyone. It's often on sale, and the DLC is few and pretty good, not too expensive either but doesn't add too much (though Great Wonders with Heirs of Alexander are cute since you can see the wonder on the map in 3D lol). It's probably the truest of the phrase "Jack of all trades, master of none, but better than the master of one", with the final clause being crucial (not to mention Jack's pretty damn good at some of these trades to the point he really does rival, or surpass, the masters).