I just started playing, after being a fan of the original X-COM for years.
I find it a bit difficult to get into the game, because of the lack of an easily reached manual, but mostly because the troops have a very strange loadout at the beginning.
As a former member of armed forces, I have to say that no army or paramilitary organization would ever send a company on a mission with such equipment. Specialized equipment like rocket and grenade launchers, and shotguns are rarely employed, and even if they are, they are always as a secondary weapon.
To illustrate, a standard infantry company would go out with mostly assault rifles, some modified with scopes, some with grenade launchers, and maybe one with a breaching shotgun.
If single-shot rocket launchers are available, each soldier will carry one on his back (note that this is talking about wartime where facing enemy armor is probable). If there is a reloadable rocket, one soldier will carry it with a little ammo in his pack, while another soldier carries most of the ammo. Same goes for machine guns - one carries weapon, one ammo, except machine gunners usually have it as their main weapon. A marksman will carry his rifle, which is a modified assault rifle with scope and tripod. Snipers work away from the platoon, with one soldier being the sniper and having the sniper rifle and an assault rifle or pistol for protection at close quarters. Together with the sniper is the spotter who helps find targets using binoculars, and provides short-medium range protection for the sniper and himself. Each soldier in the company is equipped with at least one hand grenade, excepting maybe those who have a grenade launcher mod on the rifle, as they need the space for launched grenades.
Submachine guns have no place in real combat. Neither does a grenadier who has grenades as a main weapon. This makes him useless at long range, and likely to blow up himself and his team at close range.
So I hope you see why I was frustrated to see a team loaded out with grenade launchers, rockets and riot shotguns, especially since in the 22nd century they should have learned some tactical lessons from the past.