..the importance of the captain being able to quickly and decisively cut the thrust, especially during a low-speed/high-power reject with x-wind or contamination appears to me as paramount (we practice 30 KTS cross-wind rejects from a narrow runway in the sim a lot).
Precisely why I like working at an operator where the FO handles their own thrust levers - no ambiguity at all with hands hovering over levers etc, because as you say a low speed RTO with high thrust settings/asymmetry is a scenario that requires decisive action.
FWIW when I was operating with different SOPs where the FO did not handle the levers for take off, the brief was always that hands were to be removed promptly as if the levers were slammed back hard then fingers would get trapped!
