Classes are part of Insurgency’s identity. This system prevents all players from using the same weapons and gives each player a loose role. Different classes grant access to different equipment; riflemen get rifles, breachers get SMGs and shotguns, gunners get LMGs, demolitions get more explosive options, advisors get more unique weapons (L85, Mk. 17, FAL), and marksmen get bolt actions and DMRs. Then there’s the officer and observer who get fire support. These classes work better for different playstyles, so players pick the class that fits them best.
The marksman class is one of the most difficult classes in Sandstorm because you have to find the balance between keeping the enemies at a distance and playing the objective. This also makes it one of the weakest classes if you don’t understand how to use it effectively. Also the M24 is currently underpowered and I hope it gets buffed.
The economy system isn’t really that different from CSGO. It’s a mesh between the economy system of CS and the pick 10 system of COD. There was point gain in Insurgency for completing objectives and we’ll probably see that return for Sandstorm.
The heavy carrier is useful because it allows you to carry more equipment. You get extra mags and extra explosives. Yes you can resuply after each objective in Co-op, but you have to have enough supply to complete the objective first.