Further thoughts

So in general, people would prefer it if the original steering mechanic was just put back? A few ships will occasionally go offscreen as a result, no doubt.

Pretty much.

I would think an easier way to reduce the incidence of stuff flying offscreen is to just increase the base maneuverability of engines a bit. Is it mainly dreadnoughts doing this?

Maneuverability is really strange - it’s effected by weight but not speed bonuses, and fighter maneuverability is calculated differently from the other hulls. Due to how speed is calculated, I think the turn-rate engines need more forward thrust - the weight, and the subsequent hit to your top speed, is currently hard to justify.