> do you believe that it is always the best idea to continue development regardless of estimated impacts?

Emphatically yes. The possible downsides are much smaller than the expected upside (as history shows) and we are really bad at predicting either in advance anyway (also as history shows). Finally, we really really really need those upsides to change our fate as a species currently one cosmic accident (meteorite, virus, nuclear escalation, etc) away from extinction.

Also even if the good guys stop, the bad guys will certainly accelerate - so in a competitive world there is really no advantage in voluntarily giving up technological development.