OK, first of all, the game, in its current state, is virtually bug-free. There is a bug where you could rescue a prisoner and the rescued prisoner turns hostile, but that is easily remedied. Second, sea raiders do not appear in groups of 80-120, even if they are assholes, so unless you've modified the game in some way, you're exaggerating. You are somewhat right about caravans that you escort. They simply will not enter a town if they are being chased by any kind of bandit. You must eliminate the bandit threat first. Also, caravans will almost always move more slowly than your group. This is working as designed.
Fighting multiple enemies on the ground is also working as designed although I agree, the design could be better. What you may be witnessing is the lack of melee friendly fire but it also benefits you since your swings will not harm your comrades.
Cattle can be annoying. Just remember, they will always run from you. Even when you lose sight of them, they are still moving away from you. If you want them to turn left, get behind them and to the right. Best way is to zig-zag behind them, keeping them moving in a relatively straight line. Actually best way is to ignore the "move cattle" quests altogether.
After only two days of play, 30 members in your group is too many. Their skill level will be too low to manage all but the weakest bandits, the looters. Fight as many groups of looters as you find, then move up to forest bandits and mountain bandits.
