If you wanna buy cobra - you need novice in fight. You cant buy it without ~2-4 hours of combat.
If you wanna buy ASP - you need scout and novice.
If you wanna buy Anaconda - you need master, brooker and traiblazer.
It will stop "mostly harmless" condas, and situation like this one.
No don't change it killing mostly harmless pilots who are piloting really big ships is a fun part of the game, especially if you are in a much smaller ship.
When I first got a viper a mostly harmless CMDR in a python tried to kill me (unprovoked), when his alpha strike failed he had absolutely no idea what to do he spent his time sending abusive messages when he could have jumped really easily. Handing him his rebuy was my favorite game moment so far, and that's saying something because I really enjoy the game,