okay, first off, i have noticed these things and no they arent defects. they are simply parts of the game
1. garda flak and kodiak do do roughly the same damage, but i think the kodiak has more forward facing banks, therefore it means more of its ADO (Average Damage Output) per autocannon is directed at the target it is firing at, whereby the garda does the same damage per autocannon, but on only 2 or 1 targets per weapon
2. i dont play vasari much, but i thought the Kanrak Assailant was the Vasari LRF? maybe im wrong, but im pretty sure it is
3. i agree the mine cruiser is almost useless, but its good for hit and run cluttering of an enemy GW
4. the Vasari are much more powerful than the other two races (theoretically) and therefore it was assumed that, logically, their starbase should be able to move, due to their mastery of the manipulation of normal and phase space
hope that answers your questions