Why have the no-ICs-on-islands rule?

Any impressions as compared to the first edition? I’m tempted to buy the second edition since I own the first edition already and want to double up pieces for the larger map (I did some work at Kinkos), but at the same time, I’m worried I’ll wish I had just doubled up on the original for the significantly cheaper price ($25) and the fact that it comes with ICs and same-modeled units.

Any feelings on that?

So how does this compare to the original 1942? Are any of these issues present there? What do you not like about 1942 that this game addresses? What do you not like about Second Edition that 1942 does better?

Full, 5-person turns. I’m imagining like 10 turns?