Hello Greg,
I’d consider mentioned wheel change not really a downgrade, but more as an adjustment according to requirements. 
Regarding breaking spokes - it’s the same issue than on any other bikes with them - the main problem is here uneven spoke tension.
(Which is - just think logical - more problematic with 24 spokes instead of 36.)
The receipt to avoid broken spokes is also very simple - just keep spoke tension halfways even.
Expressed in more practical words does than mean;
- You should check spoke tension (best directly after first installation) and, if necessary,
- You should be able to improve spoke tension.
I’d recommend to learn the “check spoke tension by ear” method without overdramatizing it:
It is totally sufficient to hear a clear tone (NOT the same on each spoke) but not a dull noise!
Treated like this periodically, your wheels won’t break spokes any longer.
Regarding behaviour; first of all you ride one inch or less lower, it may feel a little bit easier to pedal. With Balloons you can expect more comfort, but usually they do not last very long.
…principially, it is no problem to create extremely durable 16" wheels by using 18" hubs and 16" BMX rims, for example.
Kind regards,
Chris