Well that's good for me getting Civ 4. I love complexity in my games, and to be honest, I'm not that fussed about the combat system. I'm a good strategist, but I make for an appalling tactician.
My problem with combat in Civ IV was how boring it was. You made a stack and then you beelined it to the nearest enemy city. You didn't have to worry so much about enemy units or your supply lines as the enemy would usually pump all their units into defending their city. It was dull, dull, dull.
In Civ V, you've got to choose where you place units carefully, and you have to pay close attention to where enemy units are. In my most recent game, I went to war with the Japanese and we had only a three-tile border, so I had to move my large army through a narrow bottle-neck while also contending with Japanese counter attacks. It was the most satisfying conflict I ever had in a Civ game because my decisions about where I placed my units made a huge difference to the war, which isn't something that I felt was true of Civ IV.
Civ V does seem interesting, and while I'm not that bothered about combat, a better combat system is always welcome. I might check it out if I like Civ IV.
Hopefully by then there'll be some expansion packs as well.