@Divina_Rex: To be honest, I didn't really get a great sense of how different the combat was in the one game from the other. I actually played original Civ and the expansion back-to-back a couple of times, and combat didn't feel radically different to me. I know the developers have talked up this new combat system, but just me personally, I had a hard time differentiating.
I'm guessing the big difference is that if you're outclassed by technology, there will be an even greater difference. Before, on the ten point scale, if a tank attacked a spearmen unit, the tank would obviously instantly kill it, but the spearmen unit would somehow take off 10% of the tank's health (leaving the tank at 9/10 HP). I'm assuming that under the new system, that same spearmen unit would do significantly less damage than 10% of the tank's total health.
But yeah, when units from roughly comparable eras clash, I imagine the new combat system is probably going to function almost exactly the same.