More efficient and higher impedance speakers make a lot more sense than a more powerful amp.
^How^?
At 60 dB they are not stressing the amplifier, and unless that 60dB goes to 80dB SPL, then there is no great reason to add more watts, nor to add more sensitivity.
And if it sound good, then why change anything?
That said the Pass, and some of the others, would be nice to have… but they do not seem to be “required”.