Cross of Iron has many strong points to make it my favorite of the new releases. First, it is the best platform for playing h2h games on gameranger. It's stable with few disconnections or bugs when advancing in a campaign. This version has a user friendly scenario editor which gives you the ability to create your own custom scenarios historical or tournament style. In CoI you can play 1-15 day battles or the epic Grand Campaigns. You get to know your troops in CoI if they are lucky they could survive the full War. You have more realistic starting positions in CoI. You are not forced to deploy all 15 of your units in small corner of the map at the beginning of a battle. Also, you can fall back by fleeing into a map you just advanced from.
Cross of Iron does not have the strat layer like the newer CC versions. Many players hate the strat layer and think it was a big design error for the series ....more time playing Close Combat and less time playing RISK. CoI uses more small and medium size maps which some argue make for a better fight for both AI and h2h play. Big maps look great, but have a strong impact in gameplay especially when you still only have 15 units max.
CoI has HUNDREDS OF CUSTOM MAPS and many great mods that allow you to play WW1, alternate Eastern Front Mods, France vs Germany 1940, Finland, Real Romanians, Poland, Pacific, Western front June 44-May 45, and Vietnam. More mods are added regularly. In Cross of Iron you can use the scenario editor to create a barrage at the beginning of a battle to target 1-4 locations on a map. As far as airstrikes go, some mods have command units that use line of sight air observers. Other than the optional initial barrages, CoI is set up so that you have to kill using the units in the sandbox, no free arty and air strikes to depend on.