The problem is that Starship is meant to be the second stage stacked on Super Heavy, so they need some stowable/deployable landing leg solution.Landing on one engine seems deliberate according to the SpaceX commentary. I guess they can't be throttled down enough to land using two.
Strange about the legs, it looks as if they weren't powered down or had any locks. Personally I'd be looking for a design where the legs could be fixed. Simplicate and add more lightness.
I say they should invest in a massive fire-suppression facility spitting tons of nitrogen or CO2 in a few seconds, because the smallest little LO2 leak means that things will spiral out of control. You can't fight a fire fueled by evaporating LOX, it sustains itself, unless you really purge the area of its air. Which is difficult in an open-sky environnement. And a hard landing starting a LOX leak and starting fires on the ground (engines) will always be a possibility.