re: What game has the most 'replayability'?

CKIi, EU4, HoI(4 is about to come out.
I just got civil war II on steam and I've been obsessed with it. I'm on my second campaign and it's tough as fricking nails. That's one I see myself playing for a really long time just in nailing all the mechanics. The campaigns always start easy but in my current campaign, the union is overrunning northern Virginia in feb of 63 and making deep forays into texas and Louisiana and in my Union campaign was disasterousas as the confederacy took chicago and Detroit by the start of 65 but that was my play through thinking I'm better than the tutorial.