Which of these board designs is more suitable for a high current circuit?
I see no reason why you could not draw one like the second using wide traces instead of polygons, the only hard bit is you need to miss some of the pads with the end of the trace.

Such short traces can handle more than 5A, this is good because the RMS current in them, will be more than 5A.

Perhaps add extra solder to the trace from pin 2 to the via.