With the Marines Module and patch 1.10, Combat Mission: Shock force is where it was supposed to be originally.
Having the USMC in the game may seem pointless to some. Sort of an, "If you already have the US Army, what's the point of having Marines?" However, the Marines play completely differently from the way the Army plays.
The Army has tons of Javelin ATGMs sprinkled all over their infantry formations, which makes them excellent tank-killers. Their high degree of mechanization means that they are extremely mobile. They have excellent vehicles, making them a killer combined-arms team.
The Marines, on the other hand, hit hard and fast with lots of elite infantrymen. Marine platoons are huge, and companies are huger. Marines use different weapons from soldiers as well, favoring the M16 which gives them a much greater effective range. They are also less mechanized and less frequently supported by armor, which means that while combined arms tactics are still vital, your infantry will be the ones to win the day. However, Marines carry fewer Javelins than soldiers, so Marine anti-armor tactics are also very different.
In short, it's almost a whole new game to play with the Marines.
The patch fixes also make CM:SF much more fun to play than it used to be. Tactical AI, the way that troops conduct themselves on the field, has undergone a complete overhaul. Troops behave much more intelligently, and sometimes they can surprise you with how effective they are.
Artillery and CAS have also been improved. Anti-armor rounds from artillery frequently kill their targets, and a new radio alert system not only provides greater immersion but also lets you know what your artillery is doing. This is a major step up from before, where you had to keep your artillery menu open if you wanted to see what the big guns were up to. Furthermore, the AI will now call in artillery strikes after the start of the mission, whereas before it would only fire predesignated bombardments. With the addition of artillery-fired smoke rounds, the patch does completely change the way you approach artillery.
Granted, there are still problems out there, and some of the new features take getting used to, but the problems that exist now are largely ignorable. The Marines Module has given CM:SF a whole new life for me.