Javier Bardem is more menacing that Banderas.
Bardem is too gloomy, and not attractive enough.
Kahn is an elitist self-styled aristocrat with superior genes. That’s why Montalban was so good, he had that ‘corinthian leather’ air about him, but could get down and dirty.
Banderas may be too old though. Kahn is older than Kirk, but not by too much.