Why would a ship with no shields lie in wait in an asteroid thicket, and how do they survive for long enough to (foolishly) engage you?
The only ship with no shields (usually) would be Auto-Scouts. They survive long enough because of their crazy-high dodge rating (making them occasional Goddamn Bats).
That, and because their (automated) system deemed your attacks to be of higher priority, those drones stopped dodging the asteroids when you started fighting them.
Why does nobody use space suits (except during EVA)? They'd be very useful for repairing hull breaches or disabling the inside of automated ships.
On that note, why aren't there any emergency oxygen masks on any of the ships? They would definitely let crewmembers operate depressurized rooms for the duration of a single battle. You'd expect them to be as common as life vests on boats, but they don't exist until the Advanced Edition ... where all they do is halve health lost from asphyxiating. OSHA must have been the first casualty of the war.
I think that rather than being a casualty of war, it was a casualty of peace. Think about it, with the Federation existing for probably a really long time there likely weren't many situations where people had to fight. That, with the advent of shielding technology and automated repair drones, means there weren't many situations where people would need to wear those suits; oh, sure, they had to deal with pirates sometimes and all that, but even then the usual "feed it more power" solution that upgrading the oxygen generators is worked most of the time (unless their ships were falling apart, in which case they die anyway), and when the Federation was in its prime even that might not have been an issue. And the suits are uncomfortable to wear, and both those and the emergency oxygen masks take space, space that could be used to enhance the ships in some other way. So when the rebellion started, they did not have the suits ready, and the Federation did not have the resources to start using them whereas the rebels were still feeling confident and thought they don't need them (the standard "Titanic doesn't have enough boats but it's unsinkable" train of thoughts, only in space).
However, as time went on, and due to continuing negotiations/alliances with the anaerobic Lanius, the Federation needed to come up with something to stop the Lanius from accidentally killing their crew-mates with their oxygen-destroying bodies. Enter the Emergency Respirators augment. Due to most of the money going toward stopping the Rebels from absolutely crushing them, they aren't perfect (everyone takes half-damage from suffocation), but they're something.