The devs clearly doesn't know the concept of team balancing. Most classes are suited for offensive roles, such as the Mortar man or Artillery. Now the problem is that there are no counters or balancing done to limit said capabilities for said offensive classes, resulting into many players taking advantage of the broken mechanics such as spamming.
Another issue is for the lack of general team balancing, a premium player can really dominate the match without even trying, with top of the notch equipment, it literally requires no skill to play. Greedy and incompetent developers can really lower a game's reputation. If you were to try this game for the first time, I'd suggest to immediately drop it until the developers decided to balance things out.