I think most experienced twin engine guys would disagree with that
thinking. The vast majority of low speed maneuvering is done with
only the shifters

I agree with that.

and it becomes very intuitive to have them together,
usually to the left of the helm although Hatteras is to the right.

Anything can become intuitive.

A bizarre set-up I once encountered was rigged with the throttle and shifter
levers mounted on horizontal surface, above the rim of a vertical "destroyer"
wheel.

The starboard module had the black shifter lever outboard, and the red
throttle lever inboard. The port module had the throttle lever inboard, and the
shifter lever outboard. This placed the shifter levers at the opposite edges of
the array, making the "driving a bulldozer" crutch seem a bit more realistic.
:-) It was a little unusual, but the boat owner swore by at.

If
shifter and throttle were together it would be very easy to nail the
throttle by mistake and end up with a moving 50,000 pound problem on
your hands.

In the 10th of a second it would take to realize such a mistake (been there,
done that) that 50,000 pound boat isn't going to move very far.