Back in the day you could stop a bomber mid flight and slowly move backwards by clicking behind the bomber. The bomb cooldown was also shorter. This allowed you to eg. land 3 bombs on pgens in a quick succession. Nowadays you can't hover backwards with t1 bombers anymore (well you can but it breaks after a few meters and is super slow, also takes some skill to pull off) and it's pretty limited with t3 bombers too. With the higher attack cooldown it's better to do short passes anyways.
Yes you can still micro the bomber, you just can't* go backwards anymore. The usual use case for micro is to stop bomber mid air to let it reload so that you can get multiple bombs off in a single pass (but not against a single target like before)