Even if the original novels are better than the show, I still think it's a waste of a perfectly good premise.
So, you have this revolutionary weapons system that supposedly only women can operate. I don't really understand why the United States, Russia, China, Japan, South Korea, Israel, and the EU would willingly throw away their advantage by enacting the Alaska Treaty; it smacks of the same kind of thinking that ultimately led to the dismemberment of Czechoslovakia at the hands of the Nazis in the lead-up to World War II, but that's neither here nor there. In any case, at least it's acknowledged that the balance of power between men and women has been irreversibly altered, but as far as I know, they don't even dwell on that important detail very much. You could spin all sorts of interesting stories from what's already been given, but the author apparently just wanted to write a harem with pseudo-militaristic trappings.
Well, some lessons you have to learn the hard way, I suppose. There are some limited sci-fi elements (the IS units themselves), but for the most part it's your typical generic harem. If you want a military-themed romantic comedy, just stick to the Full Metal Panic! franchise.
Sousuke Sagara wouldn't even need an IS of his own to kick Ichika Orimura's ass. He'd kick Ichika's ass while piloting an unarmed Rk-92 Savage that's been left out in the Siberian tundra for the better part of a decade. Those ISes aren't looking so hot now, are they?